FM DS 07-12 - Plantas concentradoras.pdf

September 2010Page 1 of 120

MINING AND ORE PROCESSING FACILITIES

Table of ContentsPage

1.0 SCOPE ................................................................................................................................................... 61.1 Changes ............................................................................................................................................ 6

2.0 LOSS PREVENTION RECOMMENDATIONS ....................................................................................... 62.1 General Site ..................................................................................................................................... 62.2 Underground Mining Operations ................................................................................................... 10

2.2.1 Critical Mine Processes and Utilities ................................................................................... 102.2.2 Wood Timber Sets ............................................................................................................... 122.2.3 Vertical Shafts and Shaft Stations ...................................................................................... 142.2.4 Underground Belt Conveyors .............................................................................................. 162.2.5 Underground Explosives and Blasting Agents .................................................................... 172.2.6 Underground Service and Utility Areas ............................................................................... 182.2.7 Underground Warehousing ................................................................................................. 182.2.8 Underground Handling and Storage of Flammable Liquids ............................................... 182.2.9 Underground Handling and Storage of Compressed Gases .............................................. 192.2.10 Underground Mobile Equipment ....................................................................................... 202.2.11 Underground Fire Water Supplies and Distribution Systems ............................................ 212.2.12 Combustible Ores in Underground Metal and Non-Metal Mines ...................................... 222.2.13 Naturally Occurring Flammable Gases in Underground Metal and Non-Metal Mines ..... 222.2.14 Collapse, Cave-ins, Rock Falls and Rock Bursts in Underground Metal and Non-Metal

Mines ................................................................................................................................. 232.2.15 Ventilation Systems for Fire Control .................................................................................. 23

2.3 Surface Mining Operations ............................................................................................................ 232.3.1 Mobile Equipment at Surface Mines and Ship Loading Facilities ...................................... 232.3.2 Explosives and Blasting Agents at Surface Mines ............................................................. 252.3.3 Belt Conveyors at Surface Mines ........................................................................................ 25

2.4 Surface Ore Processing ................................................................................................................ 262.4.1 General Site ........................................................................................................................ 272.4.2 Crushing Facilities ............................................................................................................... 322.4.3 Ore Storage Buildings and Stock Piles ............................................................................... 322.4.4 Ore Concentrator Plants (Mills) ........................................................................................... 332.4.5 Powerhouse and Utilities ..................................................................................................... 452.4.6 Emission and Waste Control ............................................................................................... 462.4.7 Mobile Equipment Garages ................................................................................................. 472.4.8 Hydro-metallurgical Mineral Solvent Extraction (SX) Processes ......................................... 482.4.9 Plastic Equipment ................................................................................................................ 552.4.10 Head Frames and Mine Hoists ......................................................................................... 562.4.11 Heap Leaching ................................................................................................................... 592.4.12 Electrowinning and Electro-refining ................................................................................... 602.4.13 Tailings Ponds ................................................................................................................... 612.4.14 Production Pipelines .......................................................................................................... 622.4.15 Cross Country Rail Lines .................................................................................................. 62

2.5 Surface Coal Preparation .............................................................................................................. 622.5.1 Coal Preparation Buildings — General ............................................................................... 632.5.2 Thermal Coal Dryers ........................................................................................................... 642.5.3 Coal Dust Explosion Protection .......................................................................................... 662.5.4 Methane Explosion Protection ............................................................................................ 67

FM Global 7-12Property Loss Prevention Data Sheets 17-17

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2.5.5 Ignition source control ......................................................................................................... 672.5.6 Protection of Coal Silos ....................................................................................................... 68

3.0 SUPPORT FOR RECOMMENDATIONS ............................................................................................. 684.0 REFERENCES ....................................................................................................................................... 69

4.1 FM Global ....................................................................................................................................... 69APPENDIX A GLOSSARY OF TERMS ..................................................................................................... 70

A.1 Mineral and Ore Terms ................................................................................................................. 70A.2 Mining Terms ................................................................................................................................. 72A.3 Ore Processing and Refining Terms ............................................................................................. 89

APPENDIX B DOCUMENT REVISION HISTORY .................................................................................... 108

List of FiguresFig. 1. Photo of typical underground timber set. This set has no lagging. ................................................. 12Fig. 2. Photo of tunnel with timber sets backed by plank lagging. This arrangement always

creates a potential self sustaining fire. ............................................................................................. 13Fig. 3. Sketch of shaft and shaft station fire protection system (combination water spray and smoke

detection) developed by the US Bureau of Mines. ......................................................................... 15Fig. 4. Conveyor belt leaving underground mine portal. ............................................................................ 17Fig. 5. Underground diesel fueling station. Station is in a rock enclosure but due to rock fall potential the

rock enclosure has been supported by wood planks on steel beams and columns. ..................... 19Fig. 6. Photo of diesel fueled ore haulage vehicle in underground mine. ................................................. 20Fig. 7. Drawing of diesel fueled excavator with special suppression system in engine compartment. ..... 21Fig. 8. Self propelled 190 ton (172 tonne) ore haul truck. ......................................................................... 24Fig. 9. Large excavating shovel loading a haul truck, in a hard rock open pit mine. ................................ 25Fig. 10. Fire on a large self propelled front end loader. ............................................................................. 26Fig. 11. Walking drag line in strip coal mine. .............................................................................................. 27Fig. 12. Mobile, tracked drilling unit. ........................................................................................................... 28Fig. 13. Rail mounted ore stacker, bauxite mine. ....................................................................................... 28Fig. 14. Ore shiploader. .............................................................................................................................. 29Fig. 15. Rail mounted bucket wheel reclaimer. .......................................................................................... 30Fig. 16. Partially covered captive conveyor system feeding crushed ore from primary crusher to ore

bin, zinc mine. ................................................................................................................................ 31Fig. 17. Core storage facility. Cores are stored in wood boxes in metal racks. ........................................ 32Fig. 18. Outdoor ore stockpile with an open, elevated conveyor system feeding ore from a

nearby rushing facility. ................................................................................................................... 33Fig. 19. Simplified process flow diagram of a typical metal ore concentrator plant. ................................. 34Fig. 20. Rubber lined pipes from four separate grind circuits feeding a common rubber lined tank. ....... 35Fig. 21. View of interior of multi-grind circuit concentrator plant. Much of equipment and piping

shown has rubber linings. .............................................................................................................. 35Fig. 22. View of rubber lined inlet pipe into a hydrocyclone. ..................................................................... 36Fig. 23. Hydrocyclone bank with sprinkler protection. ................................................................................ 37Fig. 24. Warning label on rubber lined tank ............................................................................................... 38Fig. 25. Warning label hanging on pipe located directly above an open topped rubber lined tank. ......... 38Fig. 26. Drums of flammable cleaning solvent being used to clean gear teeth of large SAG mill in

copper concentrator. ...................................................................................................................... 42Fig. 27. Grouped electrical cables in multi-tier trays in concentrator building. .......................................... 43Fig. 28. Concentrator plant MCC room with high value marshalling cabinets and grouped electrical

cables at the ceiling. ...................................................................................................................... 44Fig. 29. Diesel fueled generators providing sole source electrical power at remote gold mine.

(Courtesy Rio Tinto) ....................................................................................................................... 46Fig. 30. Haulage truck inside high bay mobile equipment shop. ............................................................... 47Fig. A. Close-up of mixer-settler building with protection using foam water chamber at surface of

solvent in upper view, and deluge waterspray or foam water at ceiling in lower view. .................. 50Fig. B. Protection for building walls (external water curtain) and tank farm details ................................. 50Fig. C. Outdoor, small-cell SX facility with deluge waterspray over and under vessels and foam inside

vessels. ......................................................................................................................................... 51Fig. D. Indoor SX plant with deluge waterspray at ceiling, over mixer-settlers, under grating, under

vessels, and foam inside vessels. ................................................................................................... 51

7-1217-17 Mining and Ore Processing FacilitiesPage 2 FM Global Property Loss Prevention Data Sheets

©2010 Factory Mutual Insurance Company. All rights reserved.

Fig. E. Pulse columns with flammable organic solvents. Used in uranium and some copperextractions. Example of deluge fire protection. ............................................................................... 52

Fig. F. Sketch of recommended placement of UV/IR light detectors inside typical copper–uraniumSX settler building and inside sub-grade trenches designed to actuate protection systems andsound alarm ...................................................................................................................................... 53

Fig. G. Drainage to Remote Basin .............................................................................................................. 54Fig. 33. Plastic ducts at emission control facility, copper refinery. ............................................................. 55Fig. 34. Wire rope oiling system using sprayer enclosure and demister box. ............................................ 57Fig. 35. Wire rope oiling system using oil tray. ............................................................................................ 58Fig. 36a. Hoist brake assembly indicating areas of cracking. ..................................................................... 59Fig. 36b. Typical defects found .................................................................................................................... 60Fig. 36c. Cracks on brake shoes. ................................................................................................................ 61Fig. 37. Private cross country rail line for transporting iron ore from an inland area of Western

Australia to a coastal port. (Courtesy of Rio Tinto) ....................................................................... 63Fig. 38. Coal mining and processing facility ............................................................................................... 64Fig. 39. View of thermal dryer showing constriction deck and cyclone collection system. ....................... 65Fig. 40. Sketch of recommended placement of deluge water spray systems for constriction

deck and cyclones. ........................................................................................................................ 66Fig. 41. Flow diagram of mining and mineral processing activities from exploration to product sales. .... 68Fig. 42. Ventilation system using shafts for a deep metal mine. (Figure courtesy of Society of

Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) .......................................... 73Fig. 43. Drawing of a typical underground mine operation showing chutes, grizzlies, cribs, and typical

ground support methods. (Figure courtesy of Society of Mining, Metallurgy, andExploration, Inc. (SME), Littleton, Colorado) ................................................................................. 74

Fig. 44. Head frame structure at modern non-metal mine. Hoist house is to the left. (Courtesy of ElfAquitaine, TGI Soda, Grainger WYO) ........................................................................................... 75

Fig. 45. Close up view of head frame in Figure 44, showing wire ropes from adjacent hoist room,sheave wheel at top, and structural supports. (Courtesy of Elf Aquitaine, TGI Soda,Grainger WYO) .............................................................................................................................. 76

Fig. 46. Multi-rope, friction-sheave hoisting system, mounted in headframe. (Figure courtesy ofSociety of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ......................... 77

Fig. 47. Typical hoists found in mining operations. (Figure courtesy of Society of Mining,Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ....................................................... 78

Fig. 48. Isometric layout of an underground mine showing levels and mining terms. (Figurecourtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ...... 79

Fig. 49. Plan and cross section views of typical shafts and levels of an underground mine. (Figurecourtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ...... 80

Fig. 50. Drawing of underground metal mine supported by ore pillars. Shown is a room and pillarmining method of an inclined ore body. (Figure courtesy of Society of Mining,Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 81

Fig. 51. Drawing of a hardrock mine featuring concrete pillars which temporarily support a longwallmining zone. (Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME),Littleton, Colorado) ......................................................................................................................... 81

Fig. 52. Examples of rock bolts for ground support. (Figure courtesy of Society of Mining,Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 82

Fig. 53. Cross section view of a typical wood lined vertical shaft. (Figure courtesy of Societyof Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ....................................... 83

Fig. 54. Photograph of large open pit mine. ................................................................................................ 84Fig. 55. Ore mining of caved pit wall. (Figure courtesy of Society of Mining, Metallurgy, and

Exploration, Inc. (SME), Littleton, Colorado) .................................................................................. 84Fig. 56. Schematic view of large open pit copper mine and mills. (Bingham Canyon Mine,

Courtesy of Rio Tinto Mining, Kennecott Copper, Utah) ................................................................ 85Fig. 57. Photograph of surface strip mining of coal. Dragline is used for overburden removal. ................ 86Fig. 58. Photo of a floating dredge in a placer gold mining operation. ....................................................... 86Fig. 59. Drawing of a hydraulicking operation in a gold placer bed. (Figure courtesy of Society of

Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................... 87Fig. 60a. Section view of a single timber set used underground for ground support. ................................ 87Fig. 60b. Isometric view of a series of timber sets in an underground tunnel. ........................................... 88Fig. 60c. Section view of a timber set with wood plank lagging ................................................................. 88

7-12Mining and Ore Processing Facilities 17-17FM Global Property Loss Prevention Data Sheets Page 3


Fig. 60d. Isometric view of a series of timber sets with wood plank lagging .............................................. 88Fig. 61. Room-and-pillar mining of a flat orebody. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 89Fig. 62. Room-and-pillar mining of an inclined orebody. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 90Fig. 63. Sublevel stoping with large hole drilling and blasting. (Figure courtesy of Society of

Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................... 90Fig. 64. Sublevel stoping with ring drilling as the primary means of breaking ore. (Figure courtesy of

Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) .......................... 91Fig. 65. Shrinkage stoping in a large vertical orebody. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 91Fig. 66. Cut-and-fill mining in a large vertical orebody. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 92Fig. 67. General view of an open stoping mine. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................................ 92Fig. 68. Longwall mining of coal deposit. (Figure courtesy of Society of Mining, Metallurgy, and

Exploration, Inc. (SME), Littleton, Colorado) .................................................................................. 93Fig. 69. Sublevel caving in a large and steeply dipping orebody. (Figure courtesy of Society of

Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................................... 94Fig. 70. Block caving in a massive orebody, showing a conventional mining layout. (Figure

courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ....... 95Fig. 71. Photo of A-Frame building for bulk coal storage, with incline, totally enclosed conveyor belt

delivery and reclaim system. .......................................................................................................... 95Fig. 72. Photo of gas cooling, scrubbing, and precipitation equipment associated with a typical

emission control acid plant. Most of equipment and ducting in this photo are of fiberreinforced plastic construction. ....................................................................................................... 96

Fig. 73. Photo of a series of typical ball mills in a copper concentrator. .................................................... 97Fig. 74. Cutaway view of the interior of a ball mill. ..................................................................................... 97Fig. 75. Photo of a flotation circuit in a copper concentration mill. ............................................................. 98Fig. 76. Coal preparation plant using a hillside for gravity flow of product. ............................................... 99Fig. 77. Concentrator complex at diamond mine. (Photo courtesy of Rio Tinto) ...................................... 100Fig. 78. Gold mine concentrating facility. Due to tropical location much of process area is located

outdoors. ...................................................................................................................................... 101Fig. 79. In-pit crushing station at large copper mine. (Courtesy of Rio Tinto, Kennecott Copper,

Bingham Canyon Mine, Utah) ...................................................................................................... 102Fig. 80. Drawing of a movable crusher mounted on a crawler transporter. (Figure courtesy of

Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ....................... 102Fig. 81. Photo of a mobile crusher at open pit mining operation. (Courtesy of Alcoa) ............................ 103Fig. 82. Drawing of a gyratory crusher inside a multistory reinforced concrete crushing facility. (Figure

courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ..... 104Fig. 83. Drawing of in-situ solution mining (cyanide leaching) in an open pit. (Figure courtesy of

Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ........................ 105Fig. 84. Photo of a copper electro-refining cell (tank) house. Walkways between cells are wood plank.

Cells are concrete lined with a thin polymer plastic. (Courtesy of Cominco Quebrada, Chile) .. 105Fig. 85. Photo of plastic screen (blue) inside flotation tank. Also refer to photo of flotation circuit

under Beneficiation, above. ......................................................................................................... 106Fig. 86. Photo of world-class size semi-autogenous (SAG) mill in copper concentrator facility.

(Courtesy of Rio Tinto) ................................................................................................................ 107Fig. 87. Photo of large DC drive motor for this SAG mill. (Courtesy of Rio Tinto) .................................. 108Fig. 88. Photo of parallel ball mills in a copper concentrator facility. (Courtesy of Rio Tinto) ................. 109Fig. 89. Cutaway view drawing of a rod mill, showing internal components. .......................................... 109Fig. 90. Process flow diagram of a grind circuit featuring multiple stages of crushing with ball and

rod mill grinding. ........................................................................................................................ 110Fig. 91. Process flow diagram of a grind circuit featuring a single crusher with SAG and ball mill

grinding. ..................................................................................................................................... 110Fig. 92. Photo of a cross valley gold heap leaching operation, built into a sloping mountain. (Photo cour-

tesy of Newmont Mining Company, Yanacocha Mine, Peru) ....................................................... 111Fig. 93. Drawing of heap leach operation showing pile and pregnant solution collection pond. ............. 111Fig. 94. Closeup drawing of heap leach pile showing cyanide solution distribution system. .................. 112



Fig. 95. Photo of rubber lined raffinate pond at copper heap leaching and solvent extraction mine.(Courtesy of Cominco Quebrada, Chile) ..................................................................................... 112

Fig. 96. Photo of hydrocyclone bank (six hydrocyclones) positioned over a collection tank. Thesehydrocyclones and the discharge tank are all rubber lined. ....................................................... 113

Fig. 97. Close up view of single rubber lined hydrocyclone in bank. ....................................................... 113Fig. 98. Sketch of water injected hydrocyclone. (Figure courtesy of Society of Mining,

Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado) ..................................................... 114Fig. 99. Process flow of a typical heap leaching, carbon-in-pulp, and electrowinning circuit for

hydrometallurgical recovery of gold and silver. ........................................................................... 114Fig. 100. Typical solvent extraction process flow for copper. ................................................................... 115Fig. 101. Photo of rubber liner inside a ball mill. ....................................................................................... 115Fig. 102. Photo of rubber liner inside a large diameter steel pipe flange. ............................................... 116Fig. 103. Photo of pyrometallurgical process zinc roaster. (Photo courtesy of Cominco, Peru) .............. 117Fig. 104. Shaker screen, constructed of high density polyurethane plastic. ............................................. 118Fig. 105. Photo of SX plant at copper mine. (Photo courtesy of Cominco Quebrada, Chile) .................. 118Fig. 106. Tailings pond at zinc refinery. .................................................................................................... 119Fig. 107. Thickener tanks at copper concentrator plant. (Courtesy of Rio Tinto) .................................... 119Fig. 108. Photo of exposed plastic trommel screen at outlfow of large SAG mill. .................................. 120

List of TablesTable 1: Example of altitude corrected flash point for a material having a flash point of

105°F (41°C) at mean sea level (MSL) ........................................................................................... 8Table 2. Common flotation reagents. .......................................................................................................... 39



1.0 SCOPE

The following mining and ore processing occupancies and hazards are included in this data sheet:

• Underground and surface mining (extraction) of metal and non-metal minerals. Examples of metal mineralsare gold, silver, copper, tin, lead, tungsten, zinc, uranium, and vanadium. Non-metal minerals include sulfur,salt, potash, marble, limestone, gypsum, gemstones and aggregate rock products.

• Surface mining of fossil coal. Examples of fossil materials are anthracite and bituminous coal, lignite coal,oil shale, tar sands, peat, liquid petroleum, and natural gas. Of the fossil materials, this data sheet coversonly surface mining and preparation of coal, which includes anthracite, bituminous, and lignite grades.

• Mining and processing operations only on or under the surface of the earth or on shallow bodies of watersuch as lakes or streambeds.

• Metal and non-metal mineral processing and coal preparation which includes mineral or material transfer,sizing, washing, cleaning, drying, beneficiation, and concentration. Mineral transfer includes delivery fromthe mine to process plants, stockpiling, reclaim systems, and shipment by conveyor, rail, or other landvehicles to load out facilities including remote ship loading ports.

• Electrometallurgical (e.g., gold electrowinning, copper electro-refining) and hydrometallurgical (e.g., heapleaching and solvent extraction) refining processes.

The following mine occupancies or hazards are not included in this data sheet:

• Underground coal mining (extraction) (collieries)

• Oil shale, petroleum, tar sands and natural gas mining, extraction and processing.

• Pyrometallurgical refining processes (e.g., smelting, roasting, oxidizing, reducing, sintering or agglomeriz-ing of metals such as copper, lead, nickel, zinc and iron) and aluminum refining and smelting (which arecovered in Data Sheet 7-64/13-28, Aluminum Industry.)

• Emission control acid plants associated with smelters or ore oxidation/reduction plants

• Deep-sea extraction of minerals

• End use of refined or prepared minerals and coal (such as metal working facilities, fossil material powerplants, and coal gasification plants).

• Habitation, institutional, transportation, industrial, agricultural, manufacturing, storage, or defense uses ofunderground facilities, even if originally occupied for mineral extraction.

1.1 Changes

September 2010. Minor editorial changes were made for this revision.

2.0 LOSS PREVENTION RECOMMENDATIONS

Section 2.0 provides recommended guidance for protection of mines and ore processing plants against perilsincluding fires, explosions, miscellaneous exposures, and boiler and machinery exposures. Only propertydamage and associated business interruption exposures are covered in this document.

The risk management goal should be to improve a mining and ore processing site to qualify as a HighlyProtected Risk (HPR). Where possible in new facilities eliminate or minimize combustibles in the construc-tion and occupancy. Combustible materials should be substituted by less combustible materials wherepossible in existing facilities. Especially avoid the use of plastics in construction and occupancy to preventcostly fixed fire protection. Plastics represent severe fire potentials and cause liberation of dense smoke andby product gases which can cause direct damage to sensitive electronic equipment or impede emergencyresponse, especially in underground mines.

2.1 General Site

2.1.1 For new facilities, construct buildings, special structures, and mine passageways and shafts ofnoncombustible or fire resistive construction. The performance goal is to reduce combustible constructionloading to minimize the need for active protection systems. Plastic should be avoided, especially underground.

2.1.2 For new facilities, avoid or minimize polymeric occupancy materials such as conveyor belts, plasticcable insulation, rubber liners, plastic equipment, wood liners, plastic insulating or corrosion resistingmaterials, combustible and flammable liquids. These should be replaced by non combustible, fire safe, fire



resistant, or fire retardant materials if possible. The performance goal is to reduce combustible occupancyloading to minimize the need for active protection systems.

2.1.3 Process design, safety system design, off-premises utilities, plant construction, and general plant sitingshould take into account local or regional exposures from the following natural, catastrophic-type exposures.Licensed professional or appropriately certified engineers should be responsible for proper design wherethese exposures exist. Where exposures cannot be completely eliminated, an emergency contingency planshould be developed and documented outlining actions to be taken to eliminate or mitigate damage inadvance of pending or potential catastrophe type occurrences.

— freezing

— strong windstorm, hurricane, cyclone, typhoon, and tornado

— flood

— wildland fires

— earthquake

— volcanic activity

— snow loading

— surface water runoff

— landslide

— land subsidence

— tailing pile, heap leach pad or dam failures

— avalanche, glacier, mud or snow slide

— abandoned or active underground workings

— unusual vibration from blasting, ore processing or mobile equipment

For guidelines on these exposures refer to the following FM Global data sheets:

Data Sheet 1-0, Safeguards During Construction.

Data Sheet 1-1, Firesafe Building Construction and Materials.

Data Sheet 1-2, Earthquakes.

Data Sheet 1-28, Wind Design.

Data Sheet 1-9, Roof Anchorage.

Data Sheet 1-25, Process Tanks and Silos.

Data Sheet 1-54, Roof Loads for New Construction.

Data Sheet 1-57, Plastics in Construction

Data Sheet 1-40, Flood.

Data Sheet 9-18, Prevention of Freeze-Ups.

2.1.4 Protect process buildings, maintenance shops, parts warehouses, mobile equipment service buildings,employee housing, change houses, utility buildings, research facilities and administration offices against firesper appropriate FM Global data sheets, whether on the surface or underground. Generally, automatic sprin-klers and hydrants backed by an adequate and reliable water supply and water distribution system should beprovided where construction and/or occupancy are combustible and values and economics warrant such pro-tection. (Specific occupancy details and recommendations are covered in Sections 2.2, Underground Min-ing Operations, 2.3, Surface Mining Operations, 2.4 Surface Ore Processing, and 2.5, Surface CoalPreparation.)

2.1.5 Protect structures supporting important equipment, piping, conveyors, tramways, and electricaldistribution systems from mobile equipment impact and other mechanical damage. Signs should be postedand safe clearances designated.



2.1.6 Ensure that cutting and welding and other hot work or spark producing operations follow the FM GlobalHot Work Permit System or equivalent system, both aboveground and underground.

2.1.7 Ensure that control of combustible materials and good housekeeping are of highest priority inunderground mines, in oil lubricated hoist houses, in buildings where combustible dusts are present, in mobileequipment maintenance garages, and generally throughout the site. Housekeeping should followrecommended good practices for the occupancy. Never discard oily rags and other combustible materialssubject to spontaneous combustion in abandoned or infrequently occupied underground workings, in gobs,near wood timber sets, or near combustible ore bodies unless in special containers.

2.1.8 Control flammable and combustible liquids storage, transfer, and handling by following recognizedgood practices and data sheets 7-29, Flammable Liquid Storage in Portable Containers; 7-32, FlammableLiquid Operations; and 7-83, Drainage Systems for Flammable Liquids. Protect cutting oils in maintenancegarages or millwright shops using Data Sheet 7-37, Cutting Oils. Protect liquefied petroleum gases, such aspropane, using Data Sheet 7-55/12-28, Liquefied Petroleum Gas. Protect compressed gases in cylindersusing Data Sheet 7-50, Compressed Gases in Cylinders; Data Sheet 7-51, Acetylene; Data Sheet 7-52, Oxy-gen; and Data Sheet 7-56, MAPP Industrial Gas.

2.1.9 Protect bulk storage of diesel and other petroleum based fuels such as gasoline per Data Sheet 7-88,Storage Tanks for Flammable and Combustible Liquids.

2.1.10 Mine occupancies may be located at high altitudes. Flash points are listed relative to mean sea level(MSL); however, altitude can have a significant effect on flash point. Before determining fire protectionrequirements, adjust flammable and combustible liquid flash points for altitude by using the following equation:

EQ 1: Fc = Fsl – 0.06 (760 – P) (Derived from ASTM D56)

where:

Fc = the flash point (°F) corrected to desired altitude;

Fsl = flash point (°F) at sea level;

760 mm Hg = the average barometric pressure at sea level;

P = average barometric pressure at the given altitude, expressed in mm Hg.

(Note that Equation 1 only works in the units given. There is no metric equivalent)

Representative average barometric pressures at several different altitudes are given in Table 1. Examplecorrections for a 105°F (41°C) mean sea level (MSL) flash point combustible liquid are also given in Table 1.

Note that the example material, which is a Class II combustible liquid at MSL becomes a Class I flammableliquid at approximately 3500 ft (1067 m) and has a major impact at 14,000 ft (4268 m). This can notablyeffect the handling and protection of diesel fuel which is used in large quantities in high altitude mines.

Table 1: Example of altitude corrected flash point for a material having a flash point of105°F (41°C) at mean sea level (MSL)

Altitude Barometric Pressure(mm Hg)

Flash Pointft m °F °C

MSL MSL 760 105 411000 305 732 103 392000 610 706 102 395000 1524 632 97 368000 2439 565 93 34

10000 3048 523 91 3312000 3658 483 88 3114000 4268 446 86 30

2.1.11 Diesel fuels used in remote high altitude areas or areas subject to extreme temperatures may havelow flash point additives such as butane to enable easier mobile equipment function and engine starting.When evaluating diesel fuel handling and storage fire protection requirements, use the actual flash pointtested with the mixed additive instead of the pure diesel fuel.



2.1.12 Have administrative controls and procedures in place and backed by management to assure adequatesupervision and inspection of fire protection equipment, emergency preparedness and response, andmaintenance programs. Refer to Data Sheet 9-7/17-5, Property Conservation; Data Sheet 2-81, Fire SatefyInspections and Sprinkler System Maintenance; and other specific data sheets.

2.1.13 Control common ignition sources such as smoking, open flames, and cutting and welding byadministrative programs. Develop preventive maintenance and housekeeping programs to minimize ignitionsources from other sources such as conveying equipment, machinery, friction, hot surfaces, spontaneouscombustion, portable heaters, and the like.

2.1.14 Install all electrical equipment in accordance with Data Sheet 5-7, National Electrical Code (orinternational equivalent) throughout mill or mining areas. Protect grouped electric cables in accordance withData Sheet 5-31, Cables and Bus Bars. Establish a program of electrical maintenance in accordance withmanufacturer’s instructions and Data Sheet 5-20, Electrical Testing. Protect electrical systems against light-ning and surges as outlined in Data Sheet 5-11, Lightning Surge Protection for Electrical Systems. Under-ground mines may need special attention to lightning protection to assure metal pipes or wire ropes do notchannel surface lightning strikes to below-surface equipment.

2.1.15 Conduct predictive maintenance and testing, including non-destructive examinations (NDE), ofimportant fired, pressurized, mechanical, and electrical vessels and equipment (including mobile and semi-stationary mining vehicles) at intervals recommended by the equipment manufacturer, local codes, or asoutlined in FM Global data sheets for specific equipment. Generally, due to the harsh environment in miningoccupancies, especially underground, inspection and maintenance frequencies may need to be increased.The use of a computerized reliability based maintenance tracking and control system is advised.

2.1.16 A formal process safety management (PSM) system should be adopted where chemical processes(such as solvent extraction, ore reduction or oxidation, autoclave, acid recovery, smelting, etc.) exist. The PSMprogram should feature the following minimum requirements, as published by the American Institute ofChemical Engineers (AIChE), Center for Chemical Process Safety (CCPS), or foreign equivalents. Refer toData Sheet 7-43, Loss Prevention in Chemical Plants, for details and bibliography of selected reading ondevelopment and maintenance of PSM programs.

a) Management Accountability and Responsibility

b) Process Safety Knowledge and Documentation

c) Process Risk Management

d) Process Hazard Analysis

e) Management of Change

f) Mechanical Integrity

g) Incident Investigation

h) Training and Performance

i) Human Factors

j) Emergency Response Planning

k) Audits and Corrective Actions

2.1.19 Ensure each mine site has an emergency response capability commensurate with the exposure andthe presence or lack of nearby public or mutual aid response organizations. This capability should take intoaccount required staffing, procedures, training, equipment, and specialized needs such as proper designand emergency control of underground ventilation systems. To enable the emergency response team or plantemergency organization to be effective, event scenarios should be developed for difficult fire situations,pre-plans made, and full scale fire response simulations held at least annually. Event scenarios needingpre-planning may include, but not be limited to, underground timber set or shaft fires; underground or above-ground (highly elevated) conveyor belt fires; concealed rubber lined equipment fires; and plastic equipmentfires. Place into effect, document, and update post incident contingency plans to assure fast restoral ofproduction.



2.2 Underground Mining Operations

This section covers underground metal and non-metal mining occupancies only. Underground fossil materialmines such as oil shale or coal mines (collieries) are not covered in this document and many of the followingrecommendations may not apply to coal or oil shale mines, the goal of which is to prevent ignition of the com-bustible ore body. Surface metal, non-metal, and coal mining are covered in Section 2.3, Surface MiningOperations.

The primary fire protection goal for underground metal/non-metal mines is to protect the non-mineraloccupancies as there generally are no combustible ore seams to be ignited. A worst case fire in an under-ground metal/non-metal mine might involve consumption of all combustible materials including wood timbersets and polymeric materials in a significant mining zone but would rarely cause involvement of the entireunderground mine workings or permanent abandonment of the site as might happen in a mine withcombustible ores such as coal.

2.2.1 Critical Mine Processes and Utilities

1. Continued mine production depends on key equipment being reliable and in service. Focus identifica-tion and evaluation on the following critical equipment or utility systems to determine potential for failure orloss from risk exposures causing complete or partial mine closure. While some of these critical systems maybe located at the surface, they are usually considered part of the underground mine workings. Spares and reli-able, uninterruptable power supplies should be provided for key components of these systems. Exposuresfrom fire, explosion, rock fall, flooding, and mechanical or electrical breakdown need special evaluation.Where critical to operation, equipment and their controls should not be in unprotected combustible enclo-sures and where located underground should be protected against rock falls, cave-in, rock bursts and airblasts from explosives or high sulfide content (HSC) ore dust explosions. Highly sensitive equipment shouldbe protected against unusual vibration, diesel fuel exhaust fumes, and ore dusts.

a) Mine dewatering system — metal mines and to a lesser extent non-metal mines may be very wet fromnormal water aquifers in the mining zones. Pumps and pipelines are used to keep water levels low andout of working areas. Loss of pumping ability can cause all or portions of the mine to flood. Pumps and gearboxes may be large, of unusual service, and may have large oil lubrication systems. Loss of a singledewatering pump will rarely shut down the entire mine unless it is of critical importance and not sparedor duplicated. Flooded mines can often be dewatered over time.

b) In-Mine Electrical systems — transformers, switch rooms, emergency power systems, and electricalcable distribution systems are often located underground and are highly susceptible to fires and harshenvironmental conditions (dust, vibration, rock fall, etc.). Power to in-mine systems is usually obtainedfrom normal generating and transforming utilities on the surface via cable trays which enter via verticalor horizontal shafts and adits. Loss of a single transformer or cable tray will rarely shut down the entire mineunless it is of critical importance and not spared or duplicated. Critical electrical systems should beidentified and spares provided.

c) Mine Ventilation Systems — Ventilation systems, including blowers and controls are commonly locatedon the surface. They may be housed in combustible buildings in older facilities. Blowers fans andcompressors may be driven by large electrical motors or internal combustion engines. Large rotating equip-ment such as blowers and air compressors may have large oil lubrication systems. Spare equipment andmaximum reliability are needed for these system. Surface buildings may be susceptible to groundsubsidence if over shallow underground workings, or other natural exposure. Loss of a single mineventilation system will almost always shut down all or part of the mine.

d) Mine Cooling or Heating Systems — mines may have refrigeration or heating systems, normally locatedat the surface. The heated or cooled air is usually introduced via the ventilation system. Equipment suchas compressors or boilers may be housed in combustible buildings in older facilities. Spare equipmentand maximum reliability are needed for these system. Ammonia based systems may have an indoor explo-sion hazard. Compressors may have large oil lubrication systems. Boilers will have fuel fire and explosionhazards. Buildings may be susceptible to ground subsidence if over shallow underground workings, orother natural exposure. Loss of a mine cooling or heating system will almost always shut down the mine.

e) Mine Hoisting Machinery — Large synchronous motors, gear sets and wire ropes are used for hoistingequipment, personnel, and ore to and from the mine. They are usually located at the surface and maybe housed in combustible buildings in older facilities. They may be located underground in some mines.



Usually due to size there is only one hoist motor per hoist shaft and loss of this equipment will shut-down that shaft. Because most codes require at least two methods of safety egress from a mine, lossof one will often completely stop operations. This equipment is susceptible to fire (from lubrication andhydraulic oil systems and in some cases combustible fuels) and mechanical impact or electrical break-down or other damage such as metal fatigue. Wire ropes can sever and cause skips and cages to fall intothe shaft. Buildings may be susceptible to ground subsidence if over shallow underground workings, orbe exposed to other natural exposures.

f) Mine Production Air — Many mines use compressed air for machinery underground. Often, smallportable compressors are used for this purpose and if lost to fire or mechanical damage would notsignificantly effect production. In some cases a single large compressor has been used to supply mineproduction air via pipelines from the surface. Loss of this unit would disrupt mine operations. Thisequipment may be housed in combustible buildings in older facilities. Loss can occur from fires in oil lubri-cation systems and from mechanical breakdown. The building housing the compressor may be suscep-tible to ground subsidence if over shallow underground workings, or be exposed to other natural exposures.Pipeline distribution systems are susceptible to rockfall.

g) Mine Ore Production Processes — Some mines have primary crushing equipment underground. Thecrushed ore is then sent via conveyors or vertical hoist systems to surface secondary crushing circuits.Crushers are high value, long lead time equipment and hydraulic and lubricating oil systems and groupedelectrical cables represent fire exposures. They are designed to withstand harsh conditions but can havemechanical breakdown due to metal fatigue or sudden impact primarily. Large (usually electric) motorswhich drive crushers can suffer mechanical or electrical breakdown. Important components of crushers(such as cones, jaws or mantles and large unique motors) should be spared. Combustible fluids should beprotected. Conveyor systems should be protected. Pumps and machinery for in-situ solvent processingshould be evaluated for reliability, spares, and properly protected. Important production mining equipmentis covered below.

2. Reference the following FM Global data sheets for protection of these critical systems. In some cases,due to harsh operating conditions underground, maintenance and testing to prevent mechanical of electricalbreakdown may need to exceed guidelines intended for less harsh aboveground conditions.

Data Sheet 5-4, Transformers.

Data Sheet 5-13, Synchronous Motors.

Data Sheet 5-17, Large Electric Motors.

Data Sheet 5-18, Protection of Electrical Equipment.

Data Sheet 5-19, Switchgear and Circuit Breakers.

Data Sheet 5-20, Electrical Testing.

Data Sheet 5-23, Emergency and Standby Power Systems.

Data Sheet 5-24, Miscellaneous Electrical Equipment.

Data Sheet 5-31, Cables and Bus Bars.

Data Sheet 6 Series, Industrial Heating.

Data Sheet 7-13, Mechanical Refrigeration.

Data Sheet 7-95, Compressors.

Data Sheet 7-98, Hydraulic Fluids.

Data Sheet 12-61, Mechanical Refrigeration.

Data Sheet 13-6, Flywheels and Pulleys.

Data Sheet 13-7, Gears.

Data Sheet 13-3, Steam Turbines.

Data Sheet 13-17, Gas Turbines.

Data Sheet 13-24, Fans and Blowers.



Data Sheet 13-26, Internal Combustion Engines.

2.2.2 Wood Timber Sets

A timber set is defined as two vertical pillars and one upper cross beam (called a cap), used for supportingthe mine back. Lagging is defined as wood planks or logs placed behind or above the timber set to minimizenuisance rock falls from the walls or back of the mine tunnel.

This section applies to timbered horizontal and incline passageways up to 45° incline For inclines above45° use guidelines for vertical shafts, Section 2.2.3.

Testing by FM Global Research under contract to the United States Bureau of Mines (USBM) on fires in tim-ber sets, even without lagging, has demonstrated the potential for self propagating fire spread given the rightcombination of timber dimensions and spacing. Conversely, if the timber sets are spaced far enough apartand lagging is not present, testing shows that a fire will not self propagate beyond the incipient ignition zone,even with strong ignition sources such as fuel. Refer to USBM Information Circular (IC) 8865, 1981, ‘‘AnExperimental Investigation of the Fire Hazards Associated with Timber Sets in Mines’’, pgs 86-105.

Fig. 1. Photo of typical underground timber set. This set has no lagging.



1. Preferably, remove wood timber sets and lagging from tunnels and drifts and replace with modernnoncombustible mine support systems. Options include use of concrete, aluminum, or steel sets, rock bolting,bolted wire curtains, corrugated steel panels, or spray coating timber sets and rock surfaces with acementitious coating such as ‘‘Shotcrete’’ or ‘‘Gunite’’. (Note: new products using foamed isocyanurate basedplastic have recently been introduced. They are being marketed as suitable for structural supports for minepassageways. Claims have been made as to fire retardantcy based on small scale ASTM tunnel testing.However, until such materials have been tested and accepted or approved by FM Global Research for specificin-mine applications, they should be considered flame propagating and their use underground discouraged.)

2. Contact a FM Global Research Mine Occupancy Specialist if it is uneconomical or unfeasible to com-pletely remove or reduce wood timber sets. The specialist will conduct a focussed evaluation to determinethe potential for self sustained fire spread using results from the FM Global Research tests. Where a focussedevaluation of fire spread has not been made, it a should be assumed the timber set is self propagating untilproven otherwise. Where lagging is present, the potential for self propagating fire spread should also beassumed.

3. When a focussed evaluation of timber sets concludes self sustaining fire propagation potential or wherecontinuous wood lagging is present behind timber sets, one of the following alternative fire protectionschemes should be applied:

a) Provide automatic sprinklers, backed by an adequate and reliable water supply, throughout tunnelsand interconnected rooms having wood timber sets and/or lagging. Use pendent 165°F (74°C) sprinklersin the upright position and design to provide 0.15 gpm/ft2 (6 mm/min) density over 2000 ft2 (186 m2). Forwide tunnels two or more rows of sprinklers may be needed.

b) As an alternative to sprinkler protection cover the wood timber set or lagging with a sprayed oncementitious coating such as gunnite or shotcrete.

c) As a third but less desirable alternative, break up the timbered passageway by rated fire barriers orzones of noncombustible or protected construction every 2000 lineal feet (610 lineal meters). (Note thatbarriers may restrict ventilation control and might not be possible or practical).

Fig. 2. Photo of tunnel with timber sets backed by plank lagging. This arrangement alwayscreates a potential self sustaining fire.



i. If a fire barrier is used, it should be noncombustible, rated at two hours fire resistance, tightly sealthe passageway, and openings through the barrier should be automatic closing upon smoke detection,or be normally maintained in the closed position.

ii. If noncombustible or protected zones are used, design the length of the defined zone to at least50 times the hydraulic diameter* of the passageway. To assure fire propagation will be stopped by thedefined zone, the zone should not have significant combustible timber sets; lagging should not bepresent; and the zone should not be used for combustible storage or temporary staging of fueledvehicles. An alternative to eliminating combustibles is to provide automatic sprinkler protection in thedefined zone only. Use of polymeric materials (such as electrical cables in trays or rubber hose) arepermitted in designated noncombustible zones as long as concentration of such materials is notconsidered significant or prone to fast fire spread through the zone.

* Hydraulic diameter (Dh ) can be calculated by the following equation:

EQ 2: Dh = 2(W × H)/(W + H)

Where W = the average width of the passageway (ft or m) and H = the average height (ft or m).

Example: Assume a mine tunnel with timber sets that produce a self sustaining fire propagation with wallsan average of 20 ft (6.1 m) wide and floor-to-back (roof) height of 10 ft (3 m). Using EQ 2, Dh = 13.3 ft (4 m).To achieve non-propagation, the timber should be removed or protected for 50 times 13.3 ft (4 m) or 665 ft(202 m).

2.2.3 Vertical Shafts and Shaft Stations

A vertical shaft is one with an incline between 45% and 90%.

A shaft station is an enclosure (room) at each level where the shaft exits into a working area of the mine.The station is used for personnel ingress and egress and for delivery of supplies including fuels.

Most modern mines will have noncombustible shaft liners and steel infrastructure although wood continuesto be used in many countries. Older mines almost always have wood liners and significant wood infrastructure.Plastic liners are rare.

Metal mines are often wet and wood shaft liners may be saturated with water. Some non-metal mines, whiledrier, may have inorganic materials (such as naturally fire retardant potassium carbonate in potash mines)that have impregnated the wood lining over time. Either of these can effect potential for fire spread. When verywet liners (essentially saturated) are encountered and it is determined that this is normal and consistentthroughout the shaft (for approximately 10 hydraulic diameters above shaft stations), it is unlikely fixed firesuppression is needed. (See Equation 2 in section 2.2.2 to calculate hydraulic diameter)

1. Design new mines with noncombustible shaft liners. Preferably, in existing mine shafts remove woodtimbers, wood lagging, and other combustible liners and replace with modern noncombustible liners. Oneoption is to spray coat rock surfaces with cement or line the shaft with noncombustible materials such as metalpanels or concrete. Another is to remove only the wood lining exposed to significant ignition sources, suchas at shaft stations. Use guidelines for sprinklers, based on 10 hydraulic diameters, outlined below, for neededliner removal distances.

2. Do not use plastic liners for new mine shafts. Replace plastic liners with noncombustible liners. In existingmine shafts, protection of plastic liners should be designed based on Data Sheet 1-13, Chimneys.

3. Refer to Data Sheet 1-13, Chimneys, for general protection and prevention guidelines that are similar tolined vertical shafts.

4. If it is uneconomical or unfeasible to completely remove wood lining from inside a vertical shaft the followingshould be done:

a) Determine flame spread by submitting samples of the wood lining to FM Global Research for FirePropagation Index (FPI) testing using the FM Global Research 50 kW-scale Flammability Apparatus.(Some wet or ore impregnated wood liners have not supported vertical fire spread in shafts.)

b) If the FPI is greater than 7 (indicating self propagating fire spread, install a water deluge fire suppres-sion system inside the shaft 10 times the hydraulic diameter (Dh) above each active sublevel shaft stationentrance where fueled mobile equipment or other high energy ignition sources are or may be presentfor upcast ventilation shafts, or 10Dh below the station for downcast ventilation shafts. See Equation 2



in Section 2.2.2 for a method to determine hydraulic diameter (Dh). (Note: When ventilation direction inthe vertical shaft can be reversed [such as in a fire emergency condition] water spray protection as outlinedabove is needed both above and below the shaft station for 10 hydraulic diameters.)

Example: Using Equation 2 for Hydraulic Diameter (Dh) in Section 2.2.1.2, for a shaft dimension of 10 × 20 ft(3 by 6 m), Dh = 13.3 ft (4 m). Therefore the special deluge protection needs to extend 133 ft (40 m) abovefor upcast ventilation (or below, if ventilation is downcast) each shaft station where ignition sources arepresent.

Where sprinklers are needed they should preferably be of an open nozzle type designed in rings aroundthe inner perimeter of the shaft and sprinklers should be spaced horizontally on lines and vertically so thatall surfaces are properly wet. A minimum density of 0.25 gpm/ft2 (6 mm/min) should be provided. Detection andactuation should be by heat, smoke, light, or electrical resistance-type thermal wire actuated devices. Notethat smoke or particle counting type detectors may be sensitive to false alarm due to dust or fuel exhaustfumes common in or near shaft stations and may not be suitable.

Sprinklers should also be provided within the shaft station to protect against ignition sources such as dieselfuel and within horizontal drifts connecting into the shaft station if timber lined.

c) An alternative to sprinklers in the shaft is to cover the wood liner with a sprayed on cementitious coatingsuch as ‘‘gunnite’’ or ‘‘shotcrete’’. The wood liner should not be covered with a foamed plastic covering.

d) If the FPI is less than 7 no special fire suppression protection is needed for the shaft based on the liningitself, although the shaft station may still need sprinklers if used to move or stage combustible materials.

Fig. 3. Sketch of shaft and shaft station fire protection system (combination water spray and smoke detection) developedby the US Bureau of Mines. The system was demonstrated full scale in an underground metal mine to function prop-erly.



5. Provide FM Approved small (11⁄2 in) hose stations with at least 250 ft (76 m) of hose and fed by a watersupply at each shaft station.

6. Provide FM Approved portable multi-purpose hand held extinguishers in every hoist cage that carriespersonnel and/or supplies and at each shaft station.

7. Provide combustible or flammable liquid piping that extends downward via the vertical shaft (to feed, forexample, underground diesel fuel tanks) with automatic shutoff valves controllable from a central controlpoint and from each shaft station. Provide a shutoff valve at each shaft station and at the top of the shaft.Consider a means of detecting pipe breakage or leakage within the shaft. If possible, do not maintain flam-mable liquid transfer pipes with a permanent liquid head; empty pipes after gravity transfer.

8. Provide a fire retardant coating or other protection on grouped electrical cables with combustible polymericinsulation that enter underground mines via a vertical shaft if fuel loading and arrangement is consideredunsatisfactory based on Data Sheet 5-31, Cables and Bus Bars.

9. Provide automatic fire doors (mine stoppings) at the entrance into horizontal drifts from shaft stations,where timber sets or timber and wood lining are present in the drifts, station, or shaft. Arrange doors to closeon heat, smoke or carbon monoxide gas (CO) detection (or a combination of these detectors) and rate doorsat two hours resistance.

2.2.4 Underground Belt Conveyors

Rubber or synthetic plastic belt conveyors underground may be required by code to be rated as fire retardant,notably in underground coal mines but occasionally in metal/non-metal mines.

Some fire retardant rated belts have been shown by losses and FM Global Research testing to be capableof self sustained fire spread. International belt testing protocols do not always accurately or technically mea-sure potential for fire spread and many belts manufactured cannot be considered true non-fire propagatingunder many fire conditions encountered underground.

Currently only the FM Global Research FPI test is acceptable in this document to determine conveyor beltfire propagation potential.

Refer to Data Sheet 7-11, Belt Conveyors, for protection guidelines on conveyors and for a description ofFM Global Research FPI testing protocol and protection guidelines.

1. For best protection and where economical, provide sprinklers along the entire length of all undergroundrubber or other polymeric material based belt conveyors whether fire retardant rated or not. Refer to DataSheet 7-11, Belt Conveyors, and use guidelines for totally enclosed systems.

2. Where sprinklers are not practical, use a non-propagating conveyor belt that has been tested for FPI andlisted as Class I by FM Global Research.

As an alternative to full sprinkler protection or use of an FM Global listed Class I belt underground use thefollowing minimum guidance to limit damage and control ignition sources:

3. Protect important production* belt conveyors running in narrow, inaccessible** noncombustible tunnelsper guidelines in Data Sheet 7-11, Belt Conveyors, for totally enclosed systems. This generally means fullsprinkler protection the entire length of the beltway.

* A production belt is one that is considered critical for continued ore extraction from the mine. There maybe local belt conveying systems that can be bypassed by other belt systems or by mobile equipment thatwill reduce or eliminate production downtime. These non-critical belts may not need protection (other thanignition source control) if not in an area where they expose other combustibles such as wood timber sets.Conversely, the main belt that delivers ore to the surface can almost always be considered critical tocontinued production.

** An inaccessible tunnel is a tunnel, drift or passageway which does not lend itself to ingress for fire fight-ing equipment or vehicles. Narrow tunnels or drifts, often only slightly larger than the belt system, maybe used to connect larger tunnels.

4. Protect important production belt conveyors running in tunnels or passageways which are accessible*for manual fire fighting with automatic sprinklers over drive motors, end pulleys, or other known or commonfriction or ignition points or sources. Extend sprinklers 50 ft (15 m) beyond in both directions and space at



10 ft (3 m) intervals on lines. Design sprinkler activation to sound an alarm at a constantly attended locationand shutdown the conveyor system.

* An accessible tunnel is a tunnel which is large enough to permit easy entry of fire fighting equipmentand response personnel alongside the beltway and one that has manual fire fighting equipment such aswell spaced fire hose stations. It also requires that the fire response team is trained in conveyor belt firefighting, will respond with water hoses within 10 minutes, that the ventilation flow can be controlled, and thatthe responders have appropriate emergency gear such as self contained breathing apparatus (SCBA).

5. For all other belts not considered critical to production, provide smoke or heat detection over drive motors,pulleys, or other known friction or ignition points or sources. Extend detectors 50 ft (15 m) beyond in bothdirections from the ignition source and space at 20 ft (3 m) intervals on lines. Arrange detectors to sound analarm at a constantly attended location and shutdown the conveyor system. Note that smoke or particlecounting type detectors may be sensitive to false alarm due to dust or fuel exhaust fumes common in or nearconveyor beltways. Electric resistance type line detectors have been effectively used underground.

6. Interlock all underground conveyors to shut down and alarm on slippage, friction, misalignment, andmechanical ripping.

7. Follow all other guidelines for ignition control and protection as covered in Data Sheet 7-11, Belt Conveyors

8. Provide FM Approved small [11⁄2 in. (38 mm)] hose stations at 250 ft (76 m) intervals along accessibleconveyor systems. Design fire hose stations based on Data Sheet 4-4N, Standpipe and Hose Systems. Carryfire hose and water supply on emergency response vehicles for inaccessible areas.

2.2.5 Underground Explosives and Blasting Agents

1. Protect explosives and blasting agents used for mineral removal in accordance with Data Sheet 7-28,Energetic Materials. Protect bulk ammonium nitrate, prior to being mixed with other ingredients to produceblasting agents (such as ANFO), in accordance with Data sheet 7-89, Ammonium Nitrate and Mixed FertilizersContaining Ammonium Nitrate. Also refer to local mine regulations.

Fig. 4. Conveyor belt leaving underground mine portal.



2. Certify employees or contractors who supervise or conduct blasting on a mine site for the type of blastingagents and blasting procedures used.

2.2.6 Underground Service and Utility Areas

1. Provide safeguards for air compressors, transformers, pumps, electrical switchgear, emergencygenerators, motors, cooling systems and other service and production machinery located underground perthe appropriate FM Global Data Sheet for similar aboveground operations. Increase frequency of mainte-nance and testing when harsh conditions underground such as dust, vibration, moisture, etc.) exist. (Referto Section 2.2.1, Miscellaneous Exposures to Continued Mine Production, for a more detailed description ofcritical utility systems in underground mines and reference to several appropriate data sheets)

2. House important underground utility and fixed service equipment, especially electrical systems andequipment, in environmentally tight enclosures or otherwise separate when sensitive to exposure from dust,vibration, moisture, diesel fuel fumes, vehicle impact, etc.

3. Provide automatic sprinklers backed by an adequate water supply in underground service and utility equip-ment areas where concentrations of combustibles such as lubricating and hydraulic oils are used or storedor combustible timber sets and lagging or connecting wood walkways are present. Base the need forsprinklers on the same conditions as applied aboveground, using values, economics, manual fire fightingingress, and exposure to other equipment or areas as a guide.

From a purely property damage and production impact standpoint, sprinklers are generally only economicalin larger rooms with major concentrations of combustibles, high value equipment, and/or high business inter-ruption exposure. When equipment is scattered in smaller rooms subdivided by rock or other noncombustiblepartitions, sprinklers are generally not economical.

Where sprinklers are not provided nor needed, provide products of combustion detection to give early warningfor low value or limited exposure areas.

When deemed needed, conform sprinkler systems as much as practical to those recommended foraboveground installations.

2.2.7 Underground Warehousing

There are normally no large or high piled warehousing facilities in underground mines. Spare parts andsupplies are normally stored in small storage areas up to 10 to 15 ft (3 to 4.5 m) high due to mine back heightrestrictions. Storage may be in racks or solid piled. However, all types of commodities could be present,including plastic components and packaging. Many such small storage areas may exist.

1. Protect warehouse storage of mixed commodities per guidelines in data sheets in the 8 Series, whereeconomics and values warrant. Generally automatic sprinklers are needed for fire control or suppression whenvalues or exposure warrant.

2. Provide FM Approved Small (11⁄2 in. — 38 mm) fire hose stations near underground warehousing areas.Design fire hose stations based on Data Sheet 4-4N, Standpipe and Hose Systems.

2.2.8 Underground Handling and Storage of Flammable Liquids

There is no limit to the amount or flammable or combustible liquids allowed in underground mines as longas they are properly segregated and protected. From a risk standpoint, it is often better to store well protectedbulk quantities underground than to frequently transfer liquids from the surface. Transfer activities areinherently more susceptible to release of liquids than storage systems due to the process of making andbreaking connections.

Flammable and combustible liquids may be delivered to the underground working by pipeline or in portabletanks, in drums, or in smaller FM Approved containers. Bulk storage of liquids is usually confined to dieselfuel or lube oils for mobile equipment. Much lesser quantities of solvents or paints are kept underground.

1. Protect flammable and combustible liquids in underground mines similar to surface facilities using DataSheet 7-29, Flammable Liquid Storage in Portable Containers; Data Sheet 7-32, Flammable LiquidOperations; and Data Sheet 7-88, Storage Tanks for Flammable and Combustible Liquids. Apply guidelinesfor piping and transfer, mixing, storage, small container transfer, and ignition source control.



2. Do not permit use of Class IA flammable liquids in underground mines. Substitute Class IA flammableliquids with less hazardous liquids. (Note: most international country codes do not allow use of Class 1A liquidsunderground.)

3. Avoid use of plastic tote bins for transport or storage of combustible or flammable liquids underground.Use FM Approved transport containers wherever possible.

4. Provide an automatic fire suppression or control system for flammable and combustible liquids storageand transfer areas. Acceptable systems are automatic sprinklers, packaged AFFF or high expansion foamsystems, and packaged dry chemical or gaseous suppression systems if rooms are properly enclosed andtight. Refer to data sheets 4-0, Special Protection Systems; 4-1N, Water Spray Fixed Systems; 4-7N, LowExpansion Foam Systems; 4-10, Dry Chemical Systems; and 4-11N, Carbon Dioxide Extinguishing Systemsfor guidelines for systems other than standard sprinklers.

5. Provide fire resistant partitions rated at one hour between flammable and combustible liquids storage orhandling and other occupancies or separate the areas by physical space from important occupancies. Ifspace separation is used, establish at least 100 ft (30 m) of open area without combustible storage oroccupancy or wood timber sets. Natural rock partitions are acceptable and often preferable.

6. Provide FM Approved small (11⁄2 in. — 38 mm) fire hose stations near underground storage areas orflammable and combustible liquids handling areas. Design fire hose stations based on Data Sheet 4-4N,Standpipe and Hose Systems.

2.2.9 Underground Handling and Storage of Compressed Gases

1. Limit the amount of compressed gases stored underground to the minimum needed for practicality.Measure storage limitations against the increased hazard of frequently transporting cylinder of flammableor hazardous gas from the surface.

Fig. 5. Underground diesel fueling station. Station is in a rock enclosure but due to rock fall potential the rock enclosurehas been supported by wood planks on steel beams and columns. This room has a sprinkler system over the fueling area.



2. Use the guidelines in the following FM Global data sheets for protection of compressed gas cylinderstorage and handling:

Data Sheet 7-50, Compressed Gases in Cylinders.

Data Sheet 7-51, Acetylene.

Data Sheet 7-52, Oxygen.

Data Sheet 7-56, MAPP Industrial Gas.

3. Prohibit the use of compressed liquefied petroleum gases (LPG) such as propane in underground mines.

4. Provide FM Approved small (11⁄2 in. — 38 mm) fire hose stations near underground storage areas offlammable compressed gases. Design fire hose stations based on Data Sheet 4-4N, Standpipe and HoseSystems.

2.2.10 Underground Mobile Equipment

Mobile equipment underground may consist of loaders, haulers, jumbo drills, shotcreting units, rock boltingmachines, blast hole loaders, personnel vehicles, etc. Diesel fueled mobile equipment with rubber tires arenormally used in metal/non-metal mines. Electrically propelled equipment are commonly used in coal minesand some non-metal mines due to similarity of mining equipment to coal. Rail mounted equipment may alsobe used.

Longwall excavators, usually used in soft deposits such as coal and potash, are very large and critical piecesof equipment. While often electric powered, they feature large hydraulic systems for supporting the mineback during mining and caving.

Fully integrated tunnel boring machines that can bore up to 23 ft (7 m) in diameter are exceptionally highvalue equipment with electrical cables and hydraulic and lubrication oil systems.

Fig. 6. Photo of diesel fueled ore haulage vehicle in underground mine.



1. Protect important underground mobile or excavating equipment as it is protected on the surface, usingData Sheet 7-40/13-27, Heavy Duty Mobile Equipment. Base protection on value and production importance.

2. Protect important equipment with hydraulic fluid systems using Data Sheet 7-98, Hydraulic Fluids.

3. Do not park or stage mobile equipment using combustible fuels or oils for hydraulics and lubrication inareas identified as noncombustible zones for fire purposes (see section 2.2.2, Wood Timber Sets in Drifts andTunnels).

4. Protect underground mobile equipment maintenance facilities with automatic sprinklers and FM Approved11⁄2-in. (38 mm) fire hose stations where values, production importance, or exposure to other important areaswarrant.

5. Follow guidelines for aboveground bucket wheel excavators, draglines, stacker-reclaimers, etc. for uniqueor critical, non-spared underground equipment such tunnel boring machines and longwall excavators. Referto Section 2.3.1, Surface Mobile Equipment, for guidelines for large and critical production equipment andthe need for non-destructive analysis testing, maintenance, and inspections.

6. Where practical provide spares of critical long-lead time parts or components on large excavation equip-ment and provide a documented contingency plan to quickly obtain parts off-site (such as by participatingin a global parts-pool, for example).

2.2.11 Underground Fire Water Supplies and Distribution Systems

1. For new mines, where values and economics warrant, design fire protection water supply using appropriateaboveground fire protection guidelines for adequacy and reliability. Refer to Data Sheet 3-2, Water Tanksfor Fire Protection and Data Sheet 3-7, Fire Protection Pumps.

2. For existing mines fire protection water supply for sprinklers or hose stations may be from dedicated firewater systems or domestic or process water systems if nearby fire protection water is not economicallyavailable. Generally, gravity systems are used underground fed from sump tanks.

Sometimes due to extreme elevation differences, staged tanks are used at many levels and pressure reducingvalves may be needed. Refer to Data Sheet 3-11, Pressure Reducing Valves for Fire Protection Service.Use considerable judgement in determining equivalent reliability for water supply and distribution systemsunderground.

3. Do not exceed maximum pressures feeding sprinkler systems of 175 psig (11.9 barg) to assure properwaterspray distribution and pattern.

Fig. 7. Drawing of diesel fueled excavator with special suppression system in engine compartment.



4. Preferably, loop fire water distribution mains underground allowing an adequate water source from atleast two directions, in the event one feed direction is damaged due to fire induced rock fall. Provide sectionalshutoff valves approximately every 3000 ft (915 m) on main lines and at every lateral main feeding branchesto working areas or sprinklered rooms or equipment. Proper placement of divisional shutoff valves will allowemergency responders to access systems based on ventilation flow direction. Electrically supervise all valveson fire protection systems underground to assure proper open position.

5. Protect underground water distribution mains, where exposed in tunnels and passageways, against mobilevehicle impact, rock fall, earthquake (where appropriate in FM Global 50-year through 500-year earthquakezones as shown in Data Sheet 1-2, Earthquakes), and freezing.

2.2.12 Combustible Ores in Underground Metal and Non-Metal Mines

Some underground metal or non-metal mines have concentrations of high sulfide-content (HSC) ore or mayhave regions of coal or other combustible fossil materials. Wet HSC ores have been known to spontaneouslyignite in pockets which are not accessible to manual fire fighting, yet creating smoke and gas levels inworking areas sufficient to interrupt production or cause mine evacuation. Explosions have also occurredin HSC ore dust clouds liberated during blasting or drilling operations, creating severe underground damage.Similar incidents can also occur in localized coal deposits which are incidental to the metal mining operation.

1. Identify and document the presence of HSC ores or coal deposits susceptible to spontaneous heatingor blast induced dust explosions using modern geotechnical and analytical techniques.

2. When HSC ore bodies or coal deposits have been identified as having spontaneous heating potential,continuously monitor the deposits using carbon monoxide analyzers to give advance warning of combus-tion. Develop and document administrative procedures in advance to cope with a deep seated HSC ore or coalfire. Procedures might include fire fighting techniques and emergency passageway sealing techniques.

3. When it has been identified that drilling or blasting may take place within or loosen HSC ore bodies ornearby coal deposits, and that dust explosions might occur, implement previously developed preventivemeasures. Preventive measures might include, but are not limited to, using continuous water sprays on drillingbits to minimize dust formation and friction ignition; water mist inerting of the entire blast zone; usingpowdered limestone as drill hole grout to pleghmaticize (inert) the combustible dust; and sealing off the area.

2.2.13 Naturally Occurring Flammable Gases in Underground Metal and Non-Metal Mines

Some underground metal or non-metal mines may have concentrations of naturally occurring methane orother flammable gases such as carbon monoxide or hydrogen sulfide (caused by deep seated combustionprocesses) that may be present due to nearby coal deposits or other organic materials in the geologicstructure being mined. Ignition of concentrations of such gases that are within their explosive limits can causeunderground damage even if thousands of feet (meters) distant. Even if in unmined deposits, gas can seepinto working areas. Mines with known or potential flammable gas deposits are called Gassy Mines.

1. Identify and document the potential presence of methane or other flammable gases by modern geologicaland analytical techniques.

2. When methane or other flammable gases have been identified within a metal mine, continuously monitorventilation flow using FM Approved combustible gas detectors to give advance warning of a change in con-centration that may enter the explosive range. Place detectors in ventilation systems and arrange to soundan alarm at 10 ppm concentration in air. Concentrations over 100 ppm are considered significant trends andshould be dealt with immediately. A CO/CO2 ratio analysis can also be effectively used. Develop adminis-trative procedures in advance to understand the mine’s gas liberation trends and characteristics; acceptablelimits of gas formation; and methods to respond to adverse gas buildup such as proper ventilation controlor passageway sealing techniques. Refer to Data Sheet 5-49, Gas and Vapor Detectors and AnalysisSystems.

3. Use permissive (intrinsically safe) electrical equipment in mines identified as gassy.



2.2.14 Collapse, Cave-ins, Rock Falls and Rock Bursts in Underground Metal and Non-Metal Mines

Collapse (or cave-in) can involve localized or widespread sections of a mine. A rock fall is usually verylocalized. A rock burst occurs when a hydraulically or geologically stressed section of rock essentially ‘‘blows’’out into the tunnel environment causing local damage and far ranging overpressure effect due to air pressuredown tunnels.

The science and technology of minimizing or preventing collapse of mines, rock bursts or localized rock fallsfrom mine backs is well established and dependent on the geology and structure of the mine and ore bodyand external effects such as vibrations from blasting or equipment and from seismic events. Expertsdetermine the need for various roof and mine support systems. Roof support can vary from using miningtechniques such as room and pillar to providing localized rock bolting, shotcrete or timber sets.

1. Determine the need for and type of roof support or ore extraction methods by an expert in ground support.

2. Consider the use of rock motion detectors to determine need for and adequacy of roof support in knownunstable or highly stressed ground.

3. Protect important or critical fixed utility or production equipment from cave-in by rock bolting systems orstructures. Do not locate important equipment in areas known to be subject to stressed rock bursts.

4. Identify, document, and monitor highly stressed rock subject to sudden and violent rock bursts throughthe life of the mine.

5. Avoid or significantly restrict the use of wood timber sets and wood lagging to prevent collapse or rockfalls in new mines and properly protect timber sets where installed in older mines. (Refer to Section 2.2.1.1,Wood Timber Sets in Drifts and Tunnels)

6. Assume that polymeric structural support materials (such as expanded isocyanurate foam structuralsystems), even if rated fire retardant, are combustible and capable of self sustained fire propagation unlessthey have been tested and approved for the installation by FM Approvals. Remove such materials or coatwith a FM Approved fire retardant material.

2.2.15 Ventilation Systems for Fire Control

Underground ventilation systems can be effectively used for fire control as well as environmental control.Ventilation can have an effect not only on oxygen content (and thus the potential for fire growth or suppression)but also on the ability of emergency teams to effectively access a fire source.

1. Design underground ventilation systems as part of the overall fire response and control protocol. Preferablyretain a specialist in underground fire growth and suppression during new mine development to modelsimulated fire scenarios and provide input into ventilation design and the mine emergency plan.

2. Design ventilation systems to be operable from a central control room. If the control room might beinaccessible during a fire emergency, the ventilation system should also be controllable from aboveground.

3. Arrange ventilation to be reversible so that emergency responders may approach an underground firefrom more than one direction and from the upstream ventilation flow direction.

4. Develop, document, and update emergency response procedures at least annually based on use ofventilation to control or suppress underground mine fires. Use of computerized mine ventilation models andsimulations is encouraged. Revise the emergency plan when changes are made that may effect ventilationflow (such as addition of mine stoppings or new tunnels).

2.3 Surface Mining Operations

2.3.1 Mobile Equipment at Surface Mines and Ship Loading Facilities

1. Protect self propelled mobile equipment including large draglines, power shovels, haulage trucks, watertrucks, and front end loaders which use flammable or combustible fuels, hydraulic fluids, oil lubricatingsystems, and combustible cabling or wiring per Data Sheet 7-40/13-27, Heavy Duty Mobile Equipment.

2. Protect large, high value stationary, mobile, or semi-mobile bulk handling equipment such as earthmovers,cranes, draglines, stackers, reclaimers, stacker-reclaimers, tripper-stackers, scraper-reclaimers, bucketwheel excavators, continuous loaders, and shiploaders as follows:



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a) Protect flammable or combustible fuels, hydraulic fluids, oil lubricating systems, and combustiblecabling or wiring per Data Sheet 7-40/13-27, Heavy Duty Mobile Equipment.

b) At a minimum, protect against windstorm, collapse, toppling, metal failure, improper operation andmaintenance, fire, and earthquake according to Data Sheet 1-62, Cranes.

c) Take special care in initial design and construction of this critical and high value equipment to assure:an adequate and technically accurate design standard was used during manufacture; end use conditionswere known and conditions of potential overload or stress were determined, documented, and operatorstrained; and design audits were conducted during manufacture of the machine to assure design intent ismet.

d) Conduct a risk assessment on all existing equipment to: identify potential hazards and failure modes;analyze the overall risk; quantify and rank the risk; and provide corrective action.

e) Place key mobile or semi mobile equipment on a reliability based maintenance, non-destructive exami-nation (NDE) schedule to detect metal fatigue and potential for premature cracking or other mechanicalfailures.

f) Identify highly stressed areas on this type of equipment using working drawings or by consultation withthe manufacturer and subject to NDT (e.g., magnetic particle) in their heat affected zones to ensure theyare crack free. After initial start-up testing and examination, repeat this test at intervals not exceeding7 years for machines less than 20 years in service. For machines with more than 20 years service andothers of suspect condition and initial design or where operation is in a corrosive environment (such as asaltwater shiploader), conduct the NDE test every 5 years at a minimum.

g) Subject this equipment to a full visual internal and external examination by the manufacturer, anaccredited manufacturer representative, or an independent consultant proficient in this type of equip-ment and work at least every three years for the first 20 years, and every two years thereafter. This willallow for trends analysis and ensure the machine is satisfactory for the duties it is intended to perform.

h) Conduct life evaluation studies (e.g., finite element analysis [FEA]) after 25 years of trouble-free service,or sooner if significant design changes have been made which may compromise their integrity duringnormal operations or in an overload condition. FEA should be comprehensive and the scope of work should

Fig. 8. Self propelled 190 ton (172 tonne) ore haul truck.



include: machine condition; life expectancy; opportunities for increased performance if desired; balanceof machine; condition of critical structures (e.g., masts and booms); and condition of mechanical devices(e.g., bucket wheel shafts). The report should be comprehensive, identify areas where fatigue life isconsumed, and state with confidence that potential overloading situations have not been created bychanges. Conduct FEA in conjunction with a good visual examination and measurement of operatingconditions using strain gages.

2.3.2 Explosives and Blasting Agents at Surface Mines

1. Protect explosives and blasting agents used for mineral removal in accordance with Data Sheet 7-28,Energetic Materials. Protect bulk ammonium nitrate, prior to being mixed with other ingredients to produceblasting agents (such as ANFO), in accordance with Data sheet 7-89, Ammonium Nitrate and Mixed FertilizersContaining Ammonium Nitrate.

2. Certify employees or contractors who supervise or conduct blasting on a surface mine site for the typeof blasting agents and blasting procedures used.

2.3.3 Belt Conveyors at Surface Mines

1. Protect cross country and captive conveyor systems per Data Sheet 7-11, Belt Conveyors.

Fig. 9. Large excavating shovel loading a haul truck, in a hard rock open pit mine.



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2.4 Surface Ore Processing

The following protection guidelines, which include where appropriate references to other FM Global datasheets, are intended to cover the majority of generic exposures at metal and non-metal processing facili-ties. Surface coal preparation plants are covered separately in Section 2.5, however, protection guidelinesfor the general site should also be applied, where applicable, to coal preparation facilities.

Because of the wide variety of minerals and processing techniques it is not possible to fully cover each andevery process. Material transfer, sizing, beneficiation, and concentration processes are covered. Severalspecific chemical or electrolytic processes (i.e. solvent extraction, heap leaching, electrowinning) are givenseparate attention due to specific hazard encountered in these plants.

Specifically excluded are chemical sulfide ore oxidation and reduction processes and all pyrometallurgicalrefining processes such as sintering, smelting, and agglomeration processes (i.e., metal pelletizing andbriquetting). These are considered chemical or metal refining processes and are not strictly considered partof mining occupancies although they may be on or near a large mining site. These occupancies are coveredin other FM Global data sheets or can be evaluated by chemical or other specialists where guidelines arenot available.

A surface processing facility, supporting mining operations, will vary in size, value and complexity but willgenerally always have utilities, warehousing, flammable and combustible liquids and gases storage andhandling, mobile equipment maintenance garages, general maintenance facilities, personnel accommoda-tion, and administration buildings. It will also have processing facilities which will vary depending on theamount of processing of the ore needed to derive the desired end product. The end product might be onlya raw mined ore (run-of-mine or ROM) which is shipped elsewhere to be processed; or a concentrated orefrom a large milling and beneficiation process; or a completely refined metal from an electrowinningprocessing plant.

Fig. 10. Fire on a large self propelled front end loader.



2.4.1 General Site

1. Ensure, for all new construction in ore and coal processing plants that noncombustible building materialsare used wherever possible. Avoid plastic construction materials but where rigid foamed in place plastic wallpanels are used, assure they are FM Approved Class I panels as described in Data Sheet 1-57, Plasticsin Construction. Where expanded plastic polymers are used for weather or corrosion resistance of tanks, ves-sels, or building steel removed the covering or coat it with a FM Approved fire retardant coating.

2. Provide automatic sprinklers in important site support buildings including utility, maintenance, laboratories,and administration facilities and in processing buildings such as ore storage, crushing, grading, sizing, prepa-ration, cleaning, concentrating, and drying buildings and outdoors under tipples, trestles, bridges, flumes,ship docks and piers, etc., where construction, occupancy, or equipment is combustible and where valuesand economics permit.

When evaluating need for sprinklers, special attention should be given to combustible construction and thepresence of rubber belt conveyors, grouped electric cables, flammable flotation or solvent extractionreagents, rubber lined equipment, dust collectors and bag houses, heat transfer oil systems, lubrication andhydraulic oil systems, plastic equipment and ducts, and warehouse areas. Outdoor exposure to or fromimportant process or pollution control ducts, flumes, conveyor systems, aerial tramways, wood trestles orship docks, electrical lines, etc., where they cross over or pass near buildings should also be considered.

Fig. 11. Walking drag line in strip coal mine.



Fig. 12. Mobile, tracked drilling unit.

Fig. 13. Rail mounted ore stacker, bauxite mine.



3. Design sprinklers, when needed, based on the predominate occupancy hazard in accordance with DataSheet 3-26, Fire Protection Water Demand for Non-Storage Sprinklered Properties or occupancy-specificdata sheets, and install in accordance with the rules in Data Sheet 2-0, Installation Guidelines for Auto-matic Sprinklers. Use dry pipe systems in unheated areas except where discharge of air might create dustexplosion hazards, such as in dry coal areas. In these cases, preaction or deluge sprinkler systems are pref-erable.

4. Provide surface ore and coal processing sites with a dedicated fire protection system with an adequateand reliable water source, a properly valved and sized underground main distribution system, and standardfire hydrants or monitor nozzles. Space hydrants at approximately 250 to 300 ft (76 to 91 m) intervals. Baseadequacy and reliability of water supplies for fire protection on demands presented in Data Sheet 3-26, FireProtection Water Demand for Non-Storage Sprinklered Properties, and/or the appropriate occupancy datasheet for the hazard being protected, and Data Sheet 2-0, Installation Guidelines for Automatic Sprinklers.

Fire water distribution mains should preferably be located underground. Exceptions include permafrostregions where mains may be located abovegrade in steam traced boxes, or in tropical regions where theymay be located aboveground on pipe racks. In all cases fire water distribution systems should be protectedfrom freezing, mobile equipment impact, and other exposures (such as land subsidence, flood, etc.) wheresuch exposures exist.

5. Provide standpipes with hose connections at all operating levels of ore processing and storage build-ings in accordance with Data Sheet 4-4N, Standpipe and Hose Systems. Assure equipment includesFM Approved 11⁄2 (38 mm) hose with spray nozzles and connections for 21⁄2 in (635 mm) hose. In unheatedareas arrange standpipes on manual or dry pipe systems.

6. Protect general site flammable and combustible liquids storage and handling areas using:

Fig. 14. Ore shiploader.



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Data Sheet 7-29, Flammable Liquid Storage in Portable Containers.

Data Sheet 7-32, Flammable Liquid Operations.

Data Sheet 7-83, Drainage Systems for Flammable Liquids.

Data Sheet 7-88, Storage Tanks for Flammable and Combustible Liquids.

7. Protect general site warehousing areas in accordance with FM Global recommended practices asapplicable to include data sheets in the 8 Series.

8. When the continuity of a given external or in-house service or critical utility service (such as electric power,steam, compressed air, slurry pipelines, waste systems, etc.) or a unique or long lead time piece of productionequipment is critical to the operation, investigate the reliability of the given service or equipment.

A service or piece of equipment is considered critical if interruption of this service or equipment can resultin the shutdown of the entire operation (or a considerable part of the operation) and if restarting of theoperations will result in substantial delays and/or extensive repairs. Consequences on upstream and down-stream operations should be considered when assessing the importance (i.e., values exposed) of a givenincident.

When the probability of interruption of a critical service or piece of production equipment is consideredunacceptably high, prepare, update, and enforce a written risk management contingency plan to help mini-mize consequences of the interruption. Provide spares to minimize downtime. Develop a contingencyemergency preplan to help maximize emergency response.

Fig. 15. Rail mounted bucket wheel reclaimer.



9. Evaluate core sample storage to determine production, business or financial criticality of the samples. Ifthe samples are considered critical and a loss (fire, collapse, flood, landslide, etc.) could cause the coresto become damaged or mixed (rendering them unusable), protect the sample storage or building accordingly.

Fig. 16. Partially covered captive conveyor system feeding crushed ore from primary crusher to ore bin, zinc mine.



Where cores are critical and stored in wood or cardboard trays or in a combustible building provide automaticsprinklers, relocate to a noncombustible facility, or replace combustible trays with noncombustible trays.

2.4.2 Crushing Facilities

1. Protect cross country and captive conveyer systems in crusher facilities based on Data Sheet 7-11, BeltConveyors.

2. Provide automatic sprinklers or (if water supplies are not available) a local application automatic firesuppression system (such as foam, carbon dioxide or other gaseous systems, or dry chemical) over hydraulicand lubrication oil systems used on crushers and associated equipment when the value to continuedproduction warrants.

3. Protect grouped electrical cables on crushers against mechanical impact and protect against fire wherein sufficient quantity or concentration based on Data Sheet 5-31, Cables and Bus Bars. Protect remote, mobileswitchrooms with detection and/or suppression where combustible loading warrants.

4. Place large or unique crushers on a reliability based maintenance non-destructive examination (NDE)schedule to detect metal fatigue and potential for premature cracking or other mechanical failures and toestablish trends. Base frequency of NDE examinations on manufacturers suggested time frames and industryexperience. Where conditions are unusually harsh or trends demonstrate a need, adjust inspectionfrequencies over time.

5. Provide on-site spares of important components of single large crushers such as cones, jaws, mantlesand unusually large drive machinery.

2.4.3 Ore Storage Buildings and Stock Piles

1. Provide automatic sprinklers over feed conveyors at the top of ore piles or bins and over reclaim conveyorsbeneath piles, in accordance with Data Sheet 7-11, Belt Conveyors.

Fig. 17. Core storage facility. Cores are stored in wood boxes in metal racks. While the value of the boxes, rocks, andracks have little value, the data contained in the rock cores might be critical to longterm mining operations.



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2. Provide automatic sprinklers or (if water supplies are not available) a local automatic fire suppressionsystem (such as foam, carbon dioxide or other gaseous system, or dry chemical system) over hydraulic andlubrication oil systems used for ore reclaim equipment where production impact warrants. Refer to Data Sheet7-98, Hydraulic Fluids, for additional protection needs.

3. Provide protection for grouped electrical cables in ore storage facilities per Data Sheet 5-31, Cables andBus Bars.

4. Protect high sulfide content (HSC) ores stored outdoors against water penetration (that may promoteoxidation and spontaneous combustion) and rotate the pile based on coal piles outlined in Data Sheet 8-10,Coal and Charcoal Storage.

5. Protect large ore reclaim or stacking equipment associated with ore piles and bins as outlined in detailunder Section 2.3.1 for mobile, stationary, and semi-mobile equipment at surface mining operations.

2.4.4 Ore Concentrator Plants (Mills)

Ore concentrator facilities generally have predominantly noncombustible construction, although very old millsmay have wood construction and some newer plants are using rigid plastic wall panels. Isocyanurate basedplastic foams may be used for tank freeze protection or corrosion resistance of structural steel in areas whereacids or other corrosive reagents are in use.

The combustibility of the occupancy varies by facility and process but processing areas may have extensiveinternal rubber or plastic lining of equipment, plastic trommels, screens and rubber chutes, rubber conveyorbelts, rubber or plastic pipe and hose, combustible lubrication and hydraulic fluids, thermal oils, flammableand combustible reagents and solvents, oil filled transformers, and grouped electrical cables. Thus, while themachinery and product may be noncombustible, significant combustible loading may exist in localized areas.

Recommendations in this section on concentrating mills should also be applied to similar areas in coalpreparation plants, floating dredges, or other mineral processing facilities.

Fig. 18. Outdoor ore stockpile with an open, elevated conveyor system feeding ore from a nearby rushing facility. Ore isreclaimed by a conveyor system located in a tunnel underneath the pile, visible at lower left.



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2.4.4.1 Rubber Lined Equipment (RLE)

Rubber and other internal liners are used to improve abrasion resistance of steel equipment and piping.Severe losses have occurred in rubber liners, usually due to hot work when the system is shutdown and dry,when a fire has spread unchecked within an enclosed system. It is usually not practical to provide internalfire suppression in RLE systems and ceiling sprinklers in the building will not control a concealed fire althoughthey can keep the building cool. However, it is generally not economical to protect an entire large concen-trator facility with ceiling sprinklers if the only combustibles are the RLE and therefore the principle focus onprotection of RLE is directed towards awareness, strict control of ignition sources, fire response preplanning,and limitation of potential damage and production impact by controlling common interconnections betweengrinding circuits.

Alternate liners such as alloy steels and ceramics can also be used and are generally less expensive thanrubber. However, rubber liners represent the highest abrasion resistance of all liners and are favored andcommon in ore processing plants. Once a plant has been designed and is operating, liner materials aregenerally not interchangeable, except for smaller equipment such as hydrocyclones and pumps.

1. During the design stage of new facilities reduce the amount and continuity of rubber or other polymericliners inside equipment and piping. Suitable substitute materials are ceramics, high-alumina brick and specialalloy metals such as chromium, molybdenum, manganese and carbon steels. Bonded composites orlaminates are also available.

2. During the design stage of new facilities, evaluate the potential for fire spread though RLE and, wherepossible, improve process and equipment layout to include but not be limited to:

a) Complete separation of grinding circuits by eliminating cross connections or common head tanks.

Fig. 19. Simplified process flow diagram of a typical metal ore concentrator plant.



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Fig. 20. Rubber lined pipes from four separate grind circuits feeding a common rubber lined tank.

Fig. 21. View of interior of multi-grind circuit concentrator plant. Much of equipment and piping shown has rubber linings.



b) Provision of manual gate valves at key places in grind circuit rubber lined piping that can be closedduring maintenance operations or that can be closed by operators during a fire emergency.

c) Provision of special mill-use or fire water connections to key RLE that may be manually opened toflood a dry RLE system during a fire emergency

3. For existing facilities, explore opportunities to change rubber lining to noncombustible liners.

4. For existing facilities, where adjacent grind circuits have common connections of RL piping or equipment,investigate opportunities to separate the circuits. Where separation can not be achieved, provide gate valvesat the common point (such as at a head or thickener tank) on each pipe leading back to a grind circuit. Clearlymark these valves and close these valves during maintenance activities when the system is shut down or dry.Assure that closure of these valve is part of any hot work permit systems and part of an emergency preplan.Also provide normally closed, permanently fixed connections to process water systems where the exposureand economics warrant. Generally these connections are mounted on the side of pipes or vessels such thatwater flows by gravity into the system. They are intended to be opened only during a fire emergency to floodthe internal system and should be well labeled as to use and location.

5. When present, clearly identify and label rubber lined equipment by placards or stenciling on the side ofthe rubber lined vessel or pipe. Assure that the label indicates that internal rubber lining is present and thathot work such as cutting and welding be avoided.

6. When possible completely prohibit, by management policy, hot work for equipment with rubber linings.Use an alternative form of repair. When hot work must be done, incorporate the following provisions into theactivity:

a) Provide explicit wording in the mine hot work permit system regarding RLE. Provide a check off onthe permit as to the presence of RLE within enclosed equipment or within open tanks below a hot workoperation where hot slag may fall and precautions to be taken during the work activity, such as closing gatevalves.

Fig. 22. View of rubber lined inlet pipe into a hydrocyclone.



Fig. 23. Hydrocyclone bank with sprinkler protection.



Fig. 24. Warning label on rubber lined tank

Fig. 25. Warning label hanging on pipe located directly above an open topped rubber lined tank.



b) Assure that personnel conducting hot work on enclosed RLE or above open vessels with rubber liningreceive special hazard awareness training on rubber liner fires.

c) Cover or flood with water open tanks or openings below hot work operations and station personnelwith charged hose near the exposed vessels.

7. Ensure that the on-site fire brigade or fire department has a written pre-plan in place for emergencyresponse to each process area having RLE. This may include pre-planned options such as flooding thesystems with process water, shutting selective isolation valves between equipment or adjacent grindingcircuits, providing the ability to break apart piping, cooling external equipment with fire hose, etc., as well asbeing prepared for excessive smoke generation and concealed fire spread. Knowledge of the extent andlocation of RLE is of utmost importance in emergency response which ties closely to labeling of equipmentand knowledge of the continuity of rubber liners.

8. Where numerous side-by-side rubber lined open tanks or other open vessels are located in a discretearea of the plant, provide automatic sprinklers at ceiling level over the tank area to prevent tank-to-tank firespread when tanks are dry. As an alternative to sprinklers, when rubber lined open tanks are to be temporarilyremoved from process service, fill the tanks with water to prevent accidental interior ignition duringmaintenance operations such as cutting and welding above the tank.

9. Assure that repair or modifications to interiors of rubber lined equipment are done using the followingprecautions:

a) Use safety solvents where possible

b) Use FM Approved safety cans for flammable solvents.

c) Provide adequate safety ventilation when using flammable solvents to prevent accumulations orpocketing of vapors inside of tanks.

d) Minimize ignition sources. Provide proper electrical equipment for hazardous locations when workinginside enclosed systems with electrical fixtures (such as lights), per Data Sheet 5-1, Electrical Equipmentfor Hazardous (Classified) Locations.

e) Provide FM Approved portable fire extinguishers or charged fire hose for immediate use.

2.4.4.2 Belt Conveyors

1. Provide rubber belt conveyors located inside concentrator facilities with automatic sprinklers andappropriate shutdown interlocks using Data Sheet 7-11, Belt Conveyors, as a guideline.

2.4.4.3 Flotation Reagents

1. Segregate and protect combustible, flammable, or reactive liquid reagents such as activators in flotationor other ore beneficiation processes in accordance with Data Sheet 7-32, Flammable Liquid Operations.Where quantities are sufficient, provide an automatic water or AFFF foam sprinkler system over the storageand distribution area and provide appropriate drainage based on Data Sheet 7-83, Drainage Systems forFlammable Liquids. See Table 2 for some common flotation reagents, trade names, and flammabilitycharacteristics. Note that there are hundreds of reagents and only a sample is presented below. Some arereceived as solids but may be dissolved in combustible or flammable liquids such as alcohols, or the powdermay be combustible or explosive.

Table 2. Common flotation reagents.

Reagent Trade Names Fire HazardXanthates (Potassium Ethyl Xanthate,Sodium Isobutyl Xanthate, SodiumIsopropyl Xanthate, Potassium AmylXanthate)

Dow Z SeriesAeroXanthate 300 series

Inorganic powders, No fire hazard, butmay be dissolved in flammable solvents atplant

Mercaptobenzothiozole AeroPromoter 400 series Organic combustible powder. Powder mayexplode. Mixtures take on flammabilitycharacteristics of the solvent carrier



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Reagent Trade Names Fire HazardThionocarbanilide AeroCarbanilide 130 Organic combustible powder. Powder may

explode. Mixtures take on flammabilitycharacteristics of the solvent carrier

Fatty acids (linoic acid; oleic acid) PamakPamolynActinol

FP > 300°F (150°C)

Distilled Tall Oils Pamak 25Actinol D6LR

FP > 300°F (150°C)

Fatty Amines (coconut oil, tallow, cocoamine, hydrogenated tallow amine)

Alamine, Armeen, Arosurf,Amine, Alamac

Solid @ room temperature. May bedissolved in flammable solvents

Petroleum Sulfonates (sodium sulfonate ina fuel oil or mineral oil solvent)

Aero Promoter 800 SeriesPyronate

Takes on flammability characteristics of thesolvent carrier

Guar Derivatives Aerol 100 seriesAero Depressant 600 SeriesBurtonite 78GuartecJaguar

Organic combustible powder. Powder mayexplode. Mixtures take on flammabilitycharacteristics of the solvent carrier

Synthetic High Molecular Weight Polymers Depramin Series Varies. See MSDS SheetsLignin Sulfonates (Calcium, sodium, andammonium lignin sulfonate)

LignositeMarasperseOrzan


Starches Various BrandsRed FlocDextrin


Inorganic Depressants (Sodiumpolyphosphates, sodium dichromate,sodium ferrocyanide, fluosilicic acid.Hydroflouric acid, sodium hypochlorite,sodium cyanide, lime, sodium silicate,sodium sulfite, sulfur dioxide, zinc sulfate)

Various No fire hazard, but some may react withother combustible materials, or may betoxic which could hamper fire fightingresponse. Refer toMSDS Sheets

Methylisobutylcarbinol (MIBC)(Methylamyl alcohol)

Various FP 105°F (41°C)

Cresylic Acid (mixture of isomeric phenolsand xylenols)

Yarmor F FP > 300°F (150°C) (varies by grade)

Pine oil (terpene alcohols) GNS No. 5 FP 172°F (78°C)Polyglycol Ethers (Polypropylene methylether)

TeefrothDowfroth 200 series

FP > 200°F (94°C)(Varies by grade)

Polypropylene Glycols Ucon FrotherMinerec F2000 SeriesAerofroth 65

FP > 300°F (150°C)

High molecular weight alcohols Aerofroth 70 SeriesNalco 8836Ucon Frother

Combustible alcoholsFP varies by typeSee MSDS Sheets

Fuel oil Various Various weights and flash points. Allweights are combustible liquids

Aromatic coal tar distillates Flotation Oil #4, #634 FP > 300°F (150°C)Kerosenes Various FP 100 to 150°F

(38 to 66°C)Inorganic Activators (calcium chloride,copper sulfate, lead acetate, sodumsulfide)

Various None

2. Preferably, store bulk storage of combustible, flammable, or reactive reagents in properly diked andarranged outdoor tank farms rather than inside concentrator plants. Refer to Data Sheet 7-88, Storage Tanksfor Flammable and Combustible Liquids, for spacing and other protection guidelines.

3. Where a gravity tank (usually located at a high point in the building) is used for flammable reagent transferto cells, provide an automatic shutoff valve (interlocked to a thermal sensor) at the outlet of the tank. Locatethe reagent tank in a dike or larger concentric tank capable of holding the entire contents. Do not use plastic



tubing to transfer flammable or combustible reagents from tanks to flotation cells.

2.4.4.4 Thermal Heat Transfer Fluids

1. Assure that concentration processes using heat transfer fluids (HTF) are carefully designed for a hot oilfire exposure and segregated from other processes or important utilities such as cable trays. Generally,unless isolated and a very small system, provide automatic fixed fire suppression, such as an automaticsprinkler system, in addition to liquid spill containment and process control interlocks. Follow protectionguidelines in Data Sheet 7-99/12-19, Heat Transfer by Organic and Synthetic Fluids.

2.4.4.5 Hydraulic Fluids

1. Protect concentration processes or equipment, such as dewatering filter presses, using pressurizedcombustible hydraulic fluids by automatic sprinklers and shutdown interlocks according to guidelines in DataSheet 7-98, Hydraulic Fluids. As an alternative to sprinkler protection use a FM Approved less hazardous(fire resistive) fluid.

2. Preferably, isolate large hydraulic systems in specially designed contained and cutoff rooms with 2 hoursfire resistance.

2.4.4.6 Lubrication Oils

1. Protect lubricating (lube) oils pumping stations for large motors and gear drives by automatic sprinklers.Refer to Data Sheet 7-32, Flammable Liquid Operations and Data Sheet 7-37, Cutting Oils.

2. Preferably, locate large lube oil systems in specially designed, contained and cutoff rooms with 2 hoursfire resistance. If not in special rooms, assure that lube oil skids or stations have curbs or dikes to contain anoil spill and are separated from important utilities such as cable trays or rubber lined piping or vessels.

2.4.4.7 Grinding Mills

1. Protect drive motors and gear sets on ball, rod, autogenous, or SAG mills according to guidelines in DataSheet 5-13, Synchronous Motors; Data Sheet 5-17, Large Electric Motors; and 13-7, Gears.

2. Place grinding mills such a SAG and ball mills on a reliability based maintenance non-destructive exami-nation (NDE) schedule to detect metal fatigue and potential for premature cracking or other mechanical fail-ures. Base frequency of NDE examinations on manufacturers suggested time frames and industryexperience. Increase frequency where trend analysis reveals unusual wear or where dusty conditions merit.

3. Assure that important, high value, or long lead time production components of mills such as gears androtors for large motors are spared and spares are stored on site in environmentally sound locations.

4. Where possible eliminate rubber liners from the interiors of large important grind mills and substitute metalliners. Where rubber liners are present, follow guidelines in section 2.4.4.1.

5. When cleaning mill gear teeth and other greasy or oily surfaces during maintenance use safety solventsinstead of flammable solvents when possible. When flammable solvents must be used, follow all precautionsin FM Global flammable liquid data sheets.

In this case, drum pumps are used to pump solvent to hose fed nozzles which are used to manually spraythe gear teeth. Oily residue and excess solvent collect on the floor beneath the mill, creating a fire hazardthat is not normally present nor protected.

2.4.4.8 Electrical Systems

1. At a minimum, protect all important concentrator plant motor control centers (MCC) containing switch-gear, transformers, and motor starter sets, and rooms, tunnels, and concealed spaces containing groupedplastic insulated electrical cables with products of combustion (POC) detection arranged to sound an alarmat a constantly attended location. For highly sensitive, high unit value solid state switchgear and motor startersets, consider should using of a sensitive early warning type non-thermal detection system, with sensing unitslocated inside each control panel.



Fig. 26. Drums of flammable cleaning solvent being used to clean gear teeth of large SAG mill in copper concentrator.



2. For unusually high production, monetary value, or long lead time electronic switchgear, marshallingcabinets, Programmable Logic Controller (PLC) enclosures, or motor starter sets with solid state circuitryand significant internal combustible polymeric components, install a packaged automatic gaseous suppres-sion system inside the unit’s cabinet. As an alternative to internal protection provide a spare component onsite. This latter alternative is valid only if one cabinet of important electrical component can be involved in asingle fire incident.

3. Where grouped plastic insulated electrical power or instrumentation cable concentration or arrangementwithin MCC rooms, in cable spreading areas, in general plant areas, under floors of control rooms, insubgrade tunnels, or outdoors near transformers or switchgear rooms is sufficient, provide special protec-tion based on Data Sheet 5-33, Cables and Bus Bars. This may include such options as automatic water orgaseous based suppression systems, fire retardant coatings or coverings, physical separation of trays, orencapsulation of trays in noncombustible containment systems. Give special attention to locations wherecables are exposed to other combustible materials such as near oil filled transformers or flammable reagentareas and for long vertical runs of cable tray in high bay buildings. Where cable trays are located below areaswhere hot work is common, cover the cable trays with noncombustible shields.

4. Seal vertical or horizontal openings between adjacent rooms or upper levels with electrical cable trayswith a 1 hr fire barrier material to prevent room-to-room spread. Consider compartmentalization of unusuallylarge MCC or cable spreading areas into smaller rooms. Consider subdividing long vertical runs of cabletrays with barriers.

5. Use a less flammable insulating oil such as silicone based fluids for indoor transformers, where possible.Preferably locate combustible oil insulated transformers outdoors in special fenced and drained areas. Iflocated indoors, base need for automatic sprinkler on protection guidelines in Data Sheet 5-4/14-8,Transformers. Also follow these protection guidelines for large oil filled outdoor transformers.

6. Drain and flush indoor transformers of more than 100 gal (0.38 m3) capacity using PolychlorinatedBi-Phenyls (PCB) insulating fluids and follow guidelines in Section 2.6 of Data Sheet 5-4, Transformers.

Fig. 27. Grouped electrical cables in multi-tier trays in concentrator building.



7. Spare important large or long lead time transformers or other electrical equipment.

Fig. 28. Concentrator plant MCC room with high value marshalling cabinets and grouped electrical cables at the ceiling.



8. Where dusty conditions exist, locate highly sensitive electric or electronic equipment in pressurized roomsor enclosures. Provide proof of pressurization with alarms to warn of failure.

9. For additional protection guidelines for important electrical equipment, including electrical maintenanceand testing, refer to the following FM Global data sheets:

Data Sheet 5-18, Protection of Electrical Equipment

Data Sheet 5-19, Switchgear and Circuit Breakers

Data Sheet 5-20, Electrical Testing

Data Sheet 5-24, Miscellaneous Electrical Equipment.

Data Sheet 5-32, Electronic Data Processing Systems

Data Sheet 7-45, Instrumentation and Control in Safety Applications

2.4.4.9 Control Rooms

1. Install, protect, and maintain programmable logic controllers (PLC), computer systems, marshallingcabinets, and associated equipment, used for control of entire concentration processes (e.g., grinding orflotation circuits) or specific equipment (e.g., SAG mill) as recommended in Data Sheet 7-45Instrumentationand Control in Safety Applications, and Data Sheet 5-32, Electronic Data Processing Systems. In many casesroom or equipment flooding suppression systems are needed for these critical systems. At a minimum, installproducts of combustion detection in electronic control rooms and seal the rooms against dust and processingfumes.

2.4.4.10 Fuel Fired Process Equipment

1. Protect fuel fired process equipment such as roasters, calciners, rotary kilns, ovens, and dryers using:

Data Sheet 6-7/12-7, Fluidized Bed Combustors and Boilers

Data Sheet 6-9, Industrial Ovens and Dryers

Data Sheet 6-10, Process Furnaces

Data Sheet 6-17/13-20, Rotary Kilns and Dryers

2.4.5 Powerhouse and Utilities

1. Protect powerhouse and other utility or site support systems, such as cooling towers, emergency powersystems, compressed air systems, on site oxygen production, etc. in accordance with FM Global recom-mended practices as applicable:

Data Sheet 1-6, Cooling Towers

Data Sheet 6-2/12-63, Pulverized Coal Fired Boilers

Data Sheet 6-4/12-69, Oil- and Gas-Fired Single-Burner Boilers

Data Sheet 6-5/12-70, Oil- or Gas-Fired Multiple Burner Boilers

Data Sheet 5-3/13-2, Hydroelectric Power Plants

Data Sheet 5-4, Transformers

Data Sheet 5-19, Switchgear and Circuit Breakers

Data Sheet 5-23, Emergency and Standby Power Systems

Data Sheet 5-13, Synchronous Motors

Data Sheet 5-17, Large Electric Motors

Data Sheet 7-35, Air Separation Processes

Data Sheet 7-95, Compressors



2. Do not site new dams used for hydroelectric power generation above processing and mining operationsunless an engineering study demonstrates that the site cannot be impacted by water flow from a suddenand catastrophic dam failure.

3. Study existing dams used for hydroelectric power generation, where located above processing and miningoperations, for potential flooding of the mine site should the dam or impoundment fail. Assure that this studyincludes an evaluation of dam design and stability under various worst case scenarios (including earthquake,wave action, erosion, terrorism, etc.) by a registered professional engineer or equivalent. Provide diversionchutes below the dam if conditions warrant.

2.4.6 Emission and Waste Control

1. Protect site waste or emission control systems in accordance with FM Global recommended practicesas applicable:

Data Sheet 7-78, Industrial Exhaust Systems

Data Sheet 7-73, Dust Collectors and Collection Systems

Data Sheet 6-11, Fume Incinerators

Data Sheet 6-13/12-13, Waste Fuel-Fired Boilers

Data Sheet 1-13, Chimneys

Data Sheet 7-48, Disposal of Waste Materials

2. Provide automatic sprinkler protection for important bag houses where bags or material being collectedis combustible.

3. Provide automatic sprinklers for the interior of electrostatic precipitators where construction or materialsare combustible. Refer to Section 2.4.9 for additional guidance on plastic equipment.

Fig. 29. Diesel fueled generators providing sole source electrical power at remote gold mine. (Courtesy Rio Tinto)



2.4.7 Mobile Equipment Garages

This section applies to high bay garages used for servicing and repairing large mobile equipment such aswheeled haulage trucks and tracked railroad locomotives.

In these facilities, large, high value vehicles with rubber tires, hydraulic oil systems, lube oil systems,combustible control cables, and diesel fuel may be parked side-by-side in multiple bays. Between the truckor locomotive bays may be lube oil stations with combustible materials. In locomotive shops (but generallynot in mobile vehicle garages) indoor refueling using diesel fuels is commonly done. A fire underneath a largehaulage truck or locomotive may be concealed from ceiling sprinkler operation and effectiveness. Further,in very high bays over 60 feet (18 m), sprinkler actuation may be significantly delayed or water spray fromsprinklers may not be effective.

The following guidelines are intended to limit severe damage to a single vehicle or locomotive, reduce thepotential of fire spread to adjacent vehicles, and protect the building structure.

1. Where the ceiling of the bay above the mobile equipment is 60 feet (18 m) or less provide standard wetor dry pipe automatic sprinklers on a system designed to provide 0.45 gpm/ft2 (18 mm/min) over 5000 ft2

(12 mm/min over 460 m2) (wet pipe) or 8000 ft2 (740 m2)(dry pipe) using 165°F (75°C) heads.

2. Where the ceiling of the bay above the mobile equipment is greater than 60 feet (18 m), tailor protec-tion needs to the local conditions by conducting a risk analysis. Protection options might include but are notlimited to:

a) Provision of ceiling mounted zoned deluge sprinklers, one zone for each truck or locomotive bay,actuated by optical detectors positioned underneath or near the bottom sides of the vehicle.

b) Provision of automatic foam or water deluge monitor nozzles mounted near the sides of the vehicledesigned to rapidly throw foam under the truck or locomotive. These may be mounted on nearby structuralbuilding columns.

Fig. 30. Haulage truck inside high bay mobile equipment shop.



3. Regardless of ceiling height, where the vehicle or locomotive has a concealed subgrade space under-neath the vehicle, where fuel or lubricants are constantly present or capable of being released into the space,and where the ceiling sprinklers will not be effective, provide water or foam sprinklers for the space andconcealed vehicle surfaces subject to BLEVE (such as fuel tanks).

4. In all cases, provide FM Approved small (11⁄2 in. — 38 mm) hose stations in garages and locomotiverefueling and maintenance shops for fast incipient response.

5. Provide means to pull a burning vehicle or multiple vehicles from adjacent work bays under emergencyconditions.

6. Maintain and inspect incoming vehicles to assure tires are not overheated or other imminent ignition orfuel release sources are not present.

7. Eliminate combustibles, especially oil soaked rags, from areas between truck bays and keep areas cleanof spillage of oils or lubricants. Rags should be stored in special receptacles and frequently disposed of toprevent spontaneous ignition.

8. Consider prohibiting refueling of locomotives indoors. Where refueling of locomotives is done indoors,interlock fuel delivery lines to be quickly shutoff in the event of fire. Fully explore other opportunities forreducing amount of diesel fuel involved in a fire such as drainage, reducing pipe sizes and pump capacities,eliminating gravity feed systems, etc.

2.4.8 Hydro-metallurgical Mineral Solvent Extraction (SX) Processes

2.4.8.1 Design new SX plants using principles of Inherent Safety. Refer to DS 7-43, Loss Prevention inChemical Plants.

2.4.8.1.1 Space and locate SX plant process and utility buildings, solvent areas, and storage tanks basedon a risk assessment that considers radiant heat from pool fires, solvent drainage patterns, wind effects, andemergency response capability.

2.4.8.1.2 Design buildings, piping systems, process tanks, and other vessels using noncombustible or fire-resistive construction. Use steel or concrete where possible. Where plastic tanks or piping are unavoid-able, use a structural plastic, such as fiber reinforced plastic (FRP), instead of a thermoplastic, such aspolyethylene or polypropylene, which is subject to softening and premature failure under fire exposure. Donot use glass piping systems.

2.4.8.1.3 Eliminate or reduce below-grade spaces for tank farms, piping, and process equipment. Locateall facilities at the same grade.

2.4.8.1.4 Eliminate or reduce the use of sub-grade trenches for solvent piping systems. Locate pipes abovegrade on accessible and well-ventilated pipe racks.

2.4.8.1.5 Do not use rubber flexible couplings on solvent lines and pumps. Where flexible couplings arerequired, use steel.

2.4.8.1.6 Lower roofs and covers on tanks and process vessel to minimize the vapor-collection space aboveliquid surfaces.

2.4.8.1.7 Use seal-less or mechanical double-sealed pumps for solvents.

2.4.8.1.8 Use methods to reduce static and organic mist generation in solvent systems, such as submerg-ing in-feed nozzles, minimizing bends and restrictions in piping, reducing solvent flow velocities, and usinglow-turbulence pumps.

2.4.8.1.9 Separate process control and safety interlock instrumentation from power cables. Route instrumen-tation for safety shutdown systems well away from solvent areas.

2.4.8.1.10 Use additives that lower the resistivity of the solvent to minimize or eliminate the potential for staticelectricity generation.

2.4.8.2 For all new and existing SX facilities, provide fire detection and fire suppression as follows:

2.4.8.2.1 For large outdoor SX complexes (of the type and size typical to copper or uranium extraction fea-turing circuits of side-by-side SX buildings) provide automatic deluge water spray and/or AFFF foam-waterprotection systems as indicated below:



a) Inside under the cover or roof of mixer-settler (M-S) buildings or cells to protect the solvent pool, usingeither water or foam-water systems

b) Inside solvent or organic storage tanks that are of production importance and/or that are located withinproduction areas and potentially expose other production equipment, using an AFFF system with foamdelivery chambers

c) Around the external perimeter of plastic or wood constructed organic solvent tanks using an auto-matic open head water-only deluge system

d) Over solvent or organic transfer pumps using either water or foam-water systems

e) On or under elevated pipe racks carrying flammable solvents or organics in plastic pipes using eitherwater or foam-water systems

f) Over launders, troughs and wiers attached to M-S cells, using either water or foam-water systems

g) Inside pipe trenches with plastic pipes carrying flammable solvents or organics, using either water orfoam-water systems

h) Inside dikes enclosing solvent storage tanks when located within process areas, using a foam cham-ber delivery system.

i) Around the exterior perimeter of M-S cells or buildings if spaced closer than 50 ft (15 m) from eachother, as water curtain exposure protection from nearby cells or buildings. Use standard automatic closedhead or deluge water-only sprinklers.

j) As exposure protection for other critical equipment (such as transformers) or outside along importantbuilding walls (such as MCC rooms) that are within 50 ft (15 m) of a solvent fire area. Use standard auto-matic closed head or deluge water-only sprinklers as exposure protection.

k) If the roof of an M-S cell is more than 10 ft (3 m) above the solvent pool use AFFF foam-water dis-charge chambers along the sides of the pool to ensure faster pool fire suppression.

l) Actuate deluge or AFFF foam-water systems using a high speed detection system. In the specific caseof pipe trenches, elevated pipe racks, and cable trays, use thermal or electrical resistivity detection wire.



2.4.8.2.2 For smaller outdoor SX plants (with multiple banks of side-by-side small plastic cells of the typeand size typical to lithium, nickel, iodine, etc.) provide automatic water or foam-water deluge sprinklers overthe top of the entire cell bank. Provide internal water or foam-water protection for the interior of individualcells when there is an avenue for internal fire spread from cell to cell. See Figure C, for an example of the pro-tection layout.

Fig. A. Close-up of mixer-settler building with protection using foam water chamber at surface of solvent in upper view,and deluge waterspray or foam water at ceiling in lower view. In both cases protection is also provided over troughs and

launders and inside trenches with plastic pipes carrying solvents.

Fig. B. Protection for building walls (external water curtain) and tank farm details



2.4.8.2.3. For indoor SX processes, provide protection at the ceiling of the building housing the process,under large equipment such as raised solvent tanks, under grated or solid intermediate mezzanines, insidecells or tanks that have covers common to other process cells or tanks, or where openings into closed cellsor tanks may allow the spread of an exterior fire into the tank.

2.4.8.2.4. Where vertical process columns (such as pulsed columns) are used for solvent extraction or recov-ery, protect in accordance with DS 7-14, Chemical Process Structures. Where pulsed columns are con-structed of FRP or other structural plastic rather than steel, additional protection might be needed.

Fig. C. Outdoor, small-cell SX facility with deluge waterspray over and under vessels and foam inside vessels.

Fig. D. Indoor SX plant with deluge waterspray at ceiling, over mixer-settlers, under grating, under vessels, and foam insidevessels. Note flexible rubber couplings on pipes connecting cells.



2.4.8.2.5. Protect the surface of open mixer-settler ponds located outdoors using automatic foam cham-bers along the sides of the tank to ensure fast foam delivery. For completely open ponds that do not exposeadjacent ponds or important production processes, a manual AFFF foam delivery system is acceptable ifemergency response capability is satisfactory.

2.4.8.2.6. Design water-only sprinklers to deliver 0.25 gpm/ft2 (10 mm/min) density over an operating areaof 4000 ft2 (370 m2) using high-temperature heads or 6000 ft2 (560 m2) using low-temperature heads. Pro-vide a minimum water supply duration of 120 minutes.

2.4.8.2.7. Design AFFF systems using conventional delivery nozzles to deliver 0.16 gpm/ft2 (6.4 mm/min).Ensure foam supply is available for 20 minutes.

2.4.8.2.8. Design AFFF systems using foam delivery chambers to deliver 0.10 gpm/ft2 (6.4 mm/min). Ensurefoam supply is available for 20 minutes.

2.4.8.3 Provide high-speed, early warning fire detection, such as IR or UV detection systems (or a combina-tion of both), overlooking solvent tanks and pumps, inside enclosed mixer-settler buildings and in pipetrenches. Use thermal wire detection in piperacks or cable trays. Ensure detectors actuate fire suppressionsystems where installed.

2.4.8.4 Provide standard hydrants with hoses and monitor nozzles around and within SX plants spaced perindustrial spacing guidelines and DS 3-10, Installation of Private Service Mains and their Appurtenances.Arrange monitors in solvent areas for manual AFFF foam injection. Use a demand of 500 gpm for 100 min-utes for hose streams.

2.4.8.5 Locate bulk storage tanks of flammable or combustible solvent outdoors in a diked area per guide-lines for flammable liquid tanks in Data Sheet 7-88, Storage Tanks for Flammable and Combustible Liq-uids. Ensure they are in separate rooms or diked areas separated from process equipment or utilities.

2.4.8.6 Provide solvent extraction process areas with minimum 6 in. (150 mm) high curbing to confine andchannel solvent spills. Ensure individual curbed areas do not exceed 5000 ft2 (460 m2).

2.4.8.7 Provide emergency drainage to a remote catch basin or pond from all diked areas and pipe trenches.Design flow and storage capacity based on guidelines in Data Sheet 7-83, Drainage Systems for Flam-mable Liquids.

Fig. E. Pulse columns with flammable organic solvents. Used in uranium and some copper extractions. Example of del-uge fire protection.



2.4.8.8 Use an emergency “scuttling” system for large M-S cells, whereby operators can remotely open auto-matic valves and quickly discharge cell contents to a safe area in an emergency.

2.4.8.9 If drainage cannot economically be provided where needed, use AFFF foam-water protection sys-tems instead of water-only suppression systems.

2.4.8.10 Ensure solvents at upper levels of a process plant cannot flow to lower levels, spreading the fireand increasing damage.

2.4.8.11 Where trenches or plastic piping enter a lower-grade tank farm or pumping area, provide a wall ordike to prevent spilled liquids at the higher level from flowing into the lower area. Where plastic piping passesthough this dike or wall, provide a steel spool pipe for 10 ft (3 m) in the uphill direction, and an emergency,remotely actuated shutoff valve on the line (see Fig. G).

2.4.8.12 Provide mechanical ventilation per FM Global standards for enclosed process buildings taking suc-tion from near floor level when required, based on solvent flammability characteristics.

2.4.8.13 Provide an automatic interlock to stop flow of solvents in the event of operation of any fire protec-tion system. Interlock the fire detection system to shut off solvent pumps. Provide an automatic shutoff valveon Pregnant Liquor Supply (PLS) feed lines to prevent gravity overflowing of solvent tanks when pumps stop.Provide manual shutdown capability usable from an accessible location.

2.4.8.14 Restrict hot work in solvent areas when solvent is present or where FRP or rubber-lined tanks arepresent and empty. Follow special precautions, including use of a permit system and a combustible gasdetector, whenever hot work must take place near, on, or above such installations. Take special care dur-ing plant shutdown when plastic tanks may be dry and open.

2.4.8.15 Protect against static electricity buildup and discharge.

2.4.8.15.1. Evaluate and correct solvent piping systems with high flow velocities that produce static dis-charge. Where non-conductive solvents are used with plastic piping systems provide a conductive internalpipe liner (such as carbon) to dissipate static charges generated by liquid flow. Bond and ground the sys-tem, including at flanges. (A non-conductive fluid is one with a conductivity less than 250 pS/m).

Fig. F. Sketch of recommended placement of UV/IR light detectors inside typical copper–uranium SX settler building andinside sub-grade trenches designed to actuate protection systems and sound alarm



2.4.8.15.2. Bond and ground flammable solvent systems, vessels, pipes, and pumps. Ensure bonding is pro-vided across plastic or rubber sleeves in metal piping systems.

2.4.8.15.3. Submerge or lower solvent feed pipes where they enter solvent pools (such as inside a mixer-settler) to minimize static discharge from free-falling flammable liquids and to minimize solvent mist develop-ment.

2.4.8.15.4. Inspect piping for gypsum or “crud” (also called jarosite) buildup or other non-conductive inor-ganic coatings that might compromise conductive liners. Clean accumulations to ensure conductivity.

2.4.8.15.5. Refer to DS 5-8, Static Electricity, for additional guidance and protection requirements.

2.4.8.16 Provide electrically classified electrical equipment as required by DS 5-1, Electrical Equipment inHazardous (Classified) Locations.

2.4.8.17 Provide general area lightning protection for buildings and solvent processing areas as recom-mended for local conditions and per local codes. Refer to the following publications for reference:

a) NFPA 780, Standard for the Installation of Lightning Protection Systems

b) IEC 61024, Protection of Structures Against Lightning

c) IEEE Std 142, IEEE Recommended Practice for Grounding of Industrial and Commercial Systems

Fig. G. Drainage to Remote Basin



2.4.8.18 Operate the plant under a process safety management (PSM) system. Refer to DS 7-43, Loss Pre-vention in Chemical Plants, for details on implementing an effective PSM program.

2.4.8.19 Conduct process hazard analysis (PHA), such as a Hazop, on all new and existing SX plants. Con-duct a revalidation PHA every five years and during major changes.

2.4.8.20 Manage all changes using a Management of Change (MOC) protocol.

2.4.8.21 Ensure housekeeping is of the highest order in solvent areas. Promptly clean up solvent spills ormist accumulations. Repair leaks at pumps and flanges.

2.4.8.22 Develop procedures for overseeing contractors and for preparing sites for work. Ensure vesselsare drained into safe areas. Develop procedures to safely drain lines and vessels, when required.

2.4.8.23 Label tanks having combustible construction, such as plastic or rubber linings, as to combustibil-ity.

2.4.8.24 Refer to Data Sheet 7-32, Flammable Liquid Operations, for additional guidelines on protectingflammable/combustible liquid pumping and piping systems.

2.4.9 Plastic Equipment

1. Wherever possible in new construction, minimize or eliminate the use of plastic for equipment and ductsystems. Where used, provide fire retardantcy using antimony trioxide or the like, including in chemical linersinside ducts or equipment. (Note: fire retardant additives are effective in retarding ignition but are much lesseffective in retarding fire spread, especially on the interior of duct systems. Sole reliance on fire retardantadditives for fire protection is generally not effective.)

2. Follow all precautions under rubber lined equipment for labeling and ignition source control for plasticequipment.

Fig. 33. Plastic ducts at emission control facility, copper refinery.



3. Provide automatic sprinkler protection for concentrations of important plastic equipment located insidebuildings. Design the system to provide 0.30 gpm/ft2 (12 mm/min) coverage under solid floors or intermediatemezzanines and 0.15 gpm/ft2 (6 mm/min) under intermediate open grated mezzanines. Extend protection20 ft (6 m) in all directions beyond the equipment. In some cases protection might also be warranted for theinterior of indoor plastic ducts or large vessels. Conduct a risk assessment based on Data Sheet 7-78,Industrial Exhaust Systems to determine need and extent of internal protection.

4. Provide directional water spray protection for important plastic equipment and ductwork located outdoorsbased on a risk assessment. Focus on concentrations where large ducts cross over each other or multiplevessels are positioned side-by-side. Design the system to provide 0.15 gpm/ft2 (6 mm/min) density over theexterior surface area of coverage. For very large duct and vessel systems outdoors, use of automaticallycontrolled monitor nozzles may provide equivalent protection to fixed waterspray systems. Protection mightalso be warranted for the interior of outdoor plastic ducts or large vessels. Conduct a risk assessment basedon Data Sheet 7-78, Industrial Exhaust Systems to determine need and extent of internal protection.

5. Do not allow combustibles to be stored or combustible enclosures or buildings to be staged or constructedunder outdoor FRP exhaust or gas cleaning systems. If possible restrict fueled vehicles from being parkedor from routinely being driven under these systems. Do not allow mobile molten metal or slag movers to passdirectly under plastic duct or vessels and provide barriers against accidently spilled molten materials toprevent them from flowing into the exposed area. Label duct clearance to avoid vehicle impact.

2.4.10 Head Frames and Mine Hoists

Exposure to unprotected hoist cables from lubricating or hydraulic oil system fires inside head frames andwire rope fatigue or mechanical damage have caused cables to fail, allowing hoist cages or skips to drop intodeep mine shafts. Fires have also occurred around and in pits underneath hoist motors where oil has beenallowed to accumulate.

Mechanical failure of hoist drums, hubs, spokes, drive shafts, and gears have occurred. Large synchronouselectric drive motors have failed. Resultant damage and production downtime has been extensive due tosuch incidents.

Note that hoist motors and head frames can be located underground as well as aboveground.

1. Preferably, build new head frames of noncombustible or of fire resistive construction.

2. In head frames of combustible construction or occupancy, provide automatic sprinkler protection at everylevel. Design sprinklers based on Table 8 in Data Sheet 3-26, Fire Protection Water Demand for Non-StorageSprinklered Properties.

3. Limit ordinary combustibles and storage of lubricating and hydraulic oils inside head frames and hoisthouses to immediate needs. Ensure that housekeeping, especially in cable oiling areas is of the highest order.Do not allow excess oil spillage or overspray from oil systems, especially in pits or inaccessible areas, toaccumulate.

4. Give special attention to protection of hoist cable lubricating and hydraulic (braking) oil systems. Theseare commonly located at the top level of head frames but may also be located at intermediate levels or in thehoist motor room. Provide the following protection for these systems regardless of building construction:

a. Where possible, use FM Approved less hazardous fluids for hydraulic braking systems.

b. Provide automatic sprinklers at the ceiling over and for 20 ft (6 m) beyond combustible oil systems.Design sprinklers at the ceiling should to provide 0.25 gpm/ft2 (10 mm/min) density over the area.

c. Provide automatic sprinklers inside demisters or other enclosed oil lubricating or braking equipmentwhich have oil accumulations or overspray and through which cables pass.

d. As an alternative to part 3, provide a special extinguishing system inside oil demisters or other enclosedcable oiling equipment. Use a FM Approved carbon dioxide, dry chemical, or a gaseous suppression sys-tem.

e. When an approved less hazardous fluid is used for the hydraulic braking system and the system is cut-off vertically or horizontally by at least one hour walls/floors from lubricating systems, sprinklers are notneeded unless warranted by the presence of combustible construction or ordinary combustibles.



Cesar

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5. Provide an automatic interlock to stop circulation or pumping of oil or hydraulic fluids in the event of opera-tion of any fire protection system. This can be accomplished by interlocking oil pumps, valves in key lines,etc. Provide a manual shutdown capability, useable from an accessible location. Arrange alarms to sound ina constantly attended location upon activation of the protection system.

6. Provision should be made through administrative controls or interlocks to shut off the hoist system aftera reasonable time during a fire emergency involving the hoist cables. The most suitable time can be deter-mined by analysis of cable overheating potential without lubrication and the time needed to allow orderlyevacuation of employees inside hoist cages.

7. Protect large synchronous motors associated with hoisting operations (usually located in nearby detachedhoist houses) per Data Sheet 5-13, Synchronous Motors. Provide sprinklers in hoist drive motor houseswhen construction or occupancy — such as oil lubrication systems — are combustible.

8. Refer to Data Sheets 7-98, Hydraulic Fluids and 7-37, Cutting Oils for additional guidelines on combustibleoils and fluids.

9. Conduct an initial baseline non-destructive examination (NDE) on all mechanical hoist components (drums,hubs, spokes, drive shafts, brakes, and gears, etc.).

10. Following the baseline study, where no evidence of defects (cracking, etc.) have been found, performsubsequent NDE at least every three years.

11. Where defects are found and repairs have been made, conduct NDE annually for at least the next threeyears until trends indicate the frequency can safely be restored to three years.

12. Where a cracked component is made of cast iron, do not use weld repairs. For repair of cast ironcomponents, use cold mechanical repairs. (Older drum hoists are commonly constructed of cast iron).

Fig. 34. Wire rope oiling system using sprayer enclosure and demister box.



13. To determine the existence of cracking in mine hoist brakes, perform visual inspections as indicated inFigure 36 (areas A-D). If thick layers of paint are present on brake components, obscuring possible cracks,use magnetic particle inspection as the best NDE option. If paint needs to be removed to inspect brakes, avoiduse of shot blasting or solvents, which can further seal or obscure cracks.

14. Following large disturbances (such as flooding, earthquake, heavy rains, unusual blasting vibration, earthsubsidence, etc.), inspect and repair hoist alignment and foundations (i.e., fastener looseness, cracking,damaged grout, spalling, etc.) prior to start up of the hoist system.

15. Use the following frequencies for general hoist component inspections under normal operating conditions:

a) Hoist alignment — every three years

b) Foundation condition — daily

c) Fastener tightness- quarterly

16. Refer to the related following data sheets for additional guidance on inspections of mechanical equipment:

Data Sheet 1-62, Cranes

Data Sheet 10-3, Hot Work Management

Data Sheet 13-1, Cold Mechanical Repair

Data Sheet 17-1, Nondestructive Examinations

17. Refer to Data Sheets 5-13, Synchronous Motors and 5-17, Large Electric Motors, for guidance onmechanical and electrical inspections of hoist drive motors.

Fig. 35. Wire rope oiling system using oil tray.



2.4.11 Heap Leaching

Heap leach pads, or piles as they are commonly known, have come into popular use in the past 25 years.They are used, where allowed by regulatory authorities, in remote areas where low grade ore cannot bedeveloped by other means. They are common in the Western United States, Australia, and the Andes Regionof South America. They are almost always associated with gold, silver or copper recovery. Liquid reagents,such as acids or cyanides, are used to leach metal values from the otherwise spent ore. These reagentsare almost always environmentally damaging if released from the design containment.

1. Design heap leach pads (piles or stacks) using a third party specialist or consulting firm in heap leachpad design.

2. Design heap leach pads for earthquake, flood, and surface water runoff exposure where such exposuresexist.

3. Determine the stability of existing older heap leach pads using a specialist in leach pad design. Providepeizometers to monitor trends in slope movement or slippage when stability is in question.

4. Ensure that the layering of ore on top of plastic liners is conducted under the supervision of a pad specialistto prevent accidental (and possibly undetected) tearing or penetration of the liner which may cause a needlater to remove the ore for repairs.

5. Provide leak detection or other reliable monitoring methods to determine if the liner or solution collectionsystem has been compromised.

6. Conduct annual audits of the heap pile and solution collection system, using third party consultants whospecialize in pad design.

7. Develop and document a contingency plan outlining action to be taken should a pad slope fail or the linerbe compromised.

8. Where applicable, also follow guidelines for siting and design of tailing dams and ponds, as outlined inSection 2.4.13, for leach pads.

Fig. 36a. Hoist brake assembly indicating areas of cracking.



9. Have experts develop strict heap leach operating procedures and assure that employees are trained inand follow operating procedures.

2.4.12 Electrowinning and Electro-refining

1. For new facilities, construct electrowinning and electro-refining cells and tanks of noncombustibleconstruction such as stainless steel or concrete. Where economical, replace combustible polypropyleneplastic cells in existing plants with stainless steel or other corrosion resistant noncombustible material.

2. Where plastic, rubber lined steel, or wood cells or tanks are present provide automatic sprinkler protec-tion at ceiling level designed to 0.20 gpm/ft2 (8 mm/min) over 3000 ft2 (320 m2) (wet pipe) or 3500 ft2 (330 m2)(dry pipe) with high temperature rated heads.

3. Where flammable or combustible solvents are used in the electrolytic process follow recommendationsfor solvent extraction plants, Section 2.4.8.

4. Label plastic, rubber lined steel, and wood cells and tanks with placards or stenciling as to constructionand combustibility.

5. Avoid hot work on or near plastic, rubber lined steel, or wood cells and tanks. When needed use a hotwork permit system and take precautions similar those recommended for rubber lined equipment,Section 2.4.4.1.

6. Refer to Data Sheet 7-6, Heated Plastic and Plastic Lined Tanks, for additional guidelines for plasticelectrowinning and electro-refining cells.

Fig. 36b. Typical defects found



7. Where corrosivity of the process requires protection of building structural steel, avoid use of foamed-in-place plastic or other highly combustible corrosion coverings. When it is uneconomical to remove thesematerials, cover them with a FM Approved fire retardant coating and label as to combustibility.

2.4.13 Tailings Ponds

1. For design and siting of new tailings ponds and dams use the following guidelines. Where possible andeconomical (especially where high value property exposures or business interruption potentials exist), alsouse these guidelines for upgrading existing tailings piles:

a) Retain a certified specialist proficient in soil mechanics to design tailings dams or evaluate existingdams. In earthquake-prone areas, retain a registered specialist in earthquake dynamics and soilsliquefaction.

b) Conduct complete geologic and hydrologic studies, including underground water and soil analysis atthe proposed tailings dam site location.

c) Ensure that foundation and construction soils investigations include, but not be limited to, grain sizeand distribution, density, permeability, shear strength, moisture content, and plasticity.

d) Do not construct a new pond or dam over or near old mine workings, water bearing geological faults,outcrops, near major flood or surface water runoff routes or below landslide or avalanche-prone areas.Where such siting is desired, provide special runoff diversion chutes or upstream impoundments. Do notconstruct new dams at an elevation higher than ore processing, utility, or mining facilities unless a damfailure is assured by engineering evaluation to not impact the downstream manufacturing facilities.Construct downstream diversion chutes or impoundments as needed.

e) Do not construct foundation or starter dams with permeable clay-type materials, or where the materialis in shear and subject to saturation or ground shaking induced liquefaction.

Fig. 36c. Cracks on brake shoes.



f) Ensure that the possibility of earth tremors and liquefaction caused by sonic or other forces is consid-ered in new design. Investigate the possibility of foundation subsidence and the stability of surroundingslopes. Evaluate and implement measures to prevent wave and wind erosion.

g) Design drain lines, filter blankets, and french drains from the dam for long term, maintenance-free,non-plugging operation.

h) Design decant towers and collector lines for total saturated loading for compression, shear, and tension.

i) Do not allow piping or other structures to pass through the face of the dam or the dam foundation.

j) For unusually high dams, use cyclones to separate out coarser materials from the tailings for use asdam and wall construction base.

k) Plant the slope of impounding embankments with vegetation to help long term stabilization. Wherevegetation cannot be sustained, use geologic cover materials, chemical agents, or dust palliatives.

2. Do not site new mining and ore processing facilities below existing tailings stacks, pads, or ponds, tominimize the potential of flood damage should the stack or pond dam or wall fail.

3. Retain professional engineers or specialists to evaluate existing tailing stacks, pads or ponds to determinestability and potential for failure from various natural scenarios including earthquake and sonic inducedliquefaction and unusual rain fall, surface water, or flood. Correct discovered deficiencies by engineeringdesign or dam/dike reinforcement.

4. Install piezometer or inclinometer devices in all tailings dams to measure ground water levels and porepressures and to detect stack movement and stability changes.

5. Where flood, surface water runoff, sudden ice melt (caused by volcanic or ground heating activity), oravalanche runoff potentials present exposures to existing dams and ponds, provide permanent diversionchutes, barriers, or interceptors such as upstream ponds or dikes.

6. Annually audit and inspect, using tailings pile specialists, the integrity of existing tailing ponds and dams.Results should be documented and defiencies corrected in a timely fashion.

7. Have experts develop strict tailing ponds operating procedures and assure that employees are trainedin and follow operating procedures.

2.4.14 Production Pipelines

1. Protect cross country concentrated ore slurry or waste tailings pipelines against flood, avalanche, iceflow caused by volcanic ground heating, landslide, subsidence, vehicle impact or excess weight and otherperils that may cause the pipe to break or be damaged. For very long pipelines, consider installing redundant,well separated pipes to assure continued operation should one fail.

2.4.15 Cross Country Rail Lines

1. Protect cross country privately owned railway lines used to transport ore or concentrate to shipping portsor remote processing plants against flood, avalanche, ice flow caused by volcanic ground heating, landslide,subsidence, vehicle impact or excess weight and other perils that may cause the line, bridges or trestlesto break or be damaged. Consider installing two parallel rail lines in zones of severe exposure to assurecontinued operation should one be damaged.

2. Inspect rail lines and bridges using third party specialists at least annually. On a monthly basis conductdetailed line inspections using site personnel. Use a rail mounted vehicle to inspect the line for obstruc-tions such as animals, snow, ice, or flooding, in advance of every train. Conduct non-destructive metal fatigueanalysis on samples of steel rails periodically.

3. Develop and document a post-incident contingency plan in the event the rail line is suddenly taken outof service. Ensure that the plan includes alternate means of ore transport.

2.5 Surface Coal Preparation

The following recommendations are specific to the coal processing industry. General site and concentratorplant recommendations in Sections 2.1 and 2.4 should also be applied where applicable.



2.5.1 Coal Preparation Buildings — General

1. Construct new coal preparation plant buildings, bins, and silos of noncombustible or fire resistiveconstruction.

2. Provide automatic sprinklers in coal storage and processing buildings where construction or equipmentis combustible. Sprinklers, though desirable, may be omitted in areas of fire resistive or noncombustibleconstruction if the only combustible material present is the coal in process or storage.

Sprinklers are generally not needed inside coal storage bins, bunkers, or silos unless constructed ofcombustible materials. Sprinklers usually are needed over rubber belt conveyors, areas with significantplastics (such as congested plastic pipe chases), where plastic insulated cables are grouped, over flotationreagents, at the top of silo galleries for lubrication or hydraulic fluid systems, over thermal oil systems, andin coal reclaim tunnels for conveyors or hydraulic systems.

3. Design buildings and equipment to minimize the liberation and collection of coal dust. This could includebut not be limited to use of smooth concrete beams, boxed in steel beams, use of sloped covers on horizontalwall supports, etc. Control coal dust accumulation by constant housekeeping. Water wash down is preferredto blow down of dusts.

4. Provide damage limiting construction (explosion venting and resistant systems) for coal processingbuildings and equipment where dry coal dust can accumulate. Refer to Data Sheet 1-44, Damage LimitingConstruction, and Data Sheet 7-76, Prevention and Mitigation of Combustible Dust Explosiions and Fires forguidelines.

Fig. 37. Private cross country rail line for transporting iron ore from an inland area of Western Australia to a coastal port.(Courtesy of Rio Tinto)



5. Electrically classify coal processing buildings as follows under section 2.3.4.7, Ignition Source Control.

6. In areas where dry coal dust is present and a room explosion hazard exists, protect sprinkler piping, valvesand fittings against explosion damage as recommended in Data Sheet 7-14, Fire & Explosion Protectionfor Flammable Liquid, Flammable Gas, & Liquefied Flammable Gas Processing Equipment and SupportingStructures. Where sprinklers are installed in unheated areas with accumulated coal dusts, preferably designthe system to be deluge or preaction rather than dry pipe to avoid air discharge which could cause dustliberation and subsequent explosion.

7. Follow guidelines for control rooms, plastic equipment and piping, rubber lined equipment, flammablereagents, utilities, important equipment, etc. covered under metal concentrating plants (Section 2.4.4) for coalpreparation plants. Clearly label plastic pipes and equipment.

2.5.2 Thermal Coal Dryers

1. Install an automatic deluge water spray system inside fluidized bed and screen-type thermal dryers toprotect the constriction or screen deck against fire damage which could occur due to a hot spot or suddenflare up. Place discharge nozzles so that they will effectively cover all portions of the top surface of the deck

Fig. 38. Coal mining and processing facility



and design the system to provide a minimum density of 0.25 gpm/ft2 (10 mm/min) over the area of the deck.Actuate the system by thermal detectors located inside the dryer set at 50°F (10°C) above the maximum oper-ating temperature of the dryer.

A less desirable arrangement is to have the system arranged for manual actuation. This can be accomplishedby use of push button solenoid valves or manual control valves. Manual actuation is acceptable only ifactuators are in a constantly attended location, such as a control room, alarms are transmitted to the sameconstantly attended location, and operators are trained and given the authority to activate the system.

2. For thermal dryers using heat transfer oil (e.g., thermal disc dryers):

a) Provide automatic sprinklers throughout the building and over pumps, tanks, filters, heaters, etc. wherehot oil is stored or could be released. Pay specific attention to protection of the interior of the dryer unitwhich may be shielded from ceiling sprinklers. Design sprinklers to provide 0.25 gpm/ft2 (10 mm/min) overthe area of the building plus a 250 gpm (946 l/min) hose allowance.

b) Whenever possible, locate storage tanks and heaters of hot oil outside of the dryer building in speciallyprotected structures.

c) Provide fire or heat actuated shutoff valves at strategic points on the oil piping system to minimizethe amount of oil that could backflow in the event of breakage.

d) Refer to Data Sheet 7-99/12-19, Heat Transfer by Organic and Synthetic Fluids, for further informationand additional recommendations.

3. Provide automatic deluge water spray for the interior of collectors or cyclones into which dried coal dustfines are discharged from the dryer. Pay special attention to internal portions of ducts which are susceptibleto accumulations of coal. Design the system to provide 0.25 gpm/ft2 (10 mm/min) density over the internalsurface area. When multiple cyclones or collectors are used, it is often preferable to have multiple smalldeluge systems instead of one large system.

Fig. 39. View of thermal dryer showing constriction deck and cyclone collection system.



4. Provide combustion safeguards for all fuel fired thermal dryers per Data Sheet 6-2/12-63, Pulverized Coal-Fired Boilers, Data Sheet 6-9, Industrial Ovens and Dryers, or Data Sheet 6-24/13-21, Coal Pulverizers andPulverizing Systems, which ever is most appropriate.

5. In addition to combustion safeguards, discontinue fuel firing when:

a) High temperature exists in the dryer above the constriction or screen deck (screen and fluidized beddryers), in the drying chamber (flash dryers), in discharge ducts from the dryer, and in cyclones. Settemperature sensors 50°F (10°C) above the normal operating temperature for the zone in question.

b) Process waterflow is lost to wet scrubbers which may be used to clean the coal dust laden air streamprior to discharge to atmosphere. Conversely, design the system so that fuel cannot be fired prior toscrubber water being in operation.

c) Internal fire protection water spray over the constriction deck operates.

d) Wet coal infeed into the dryer or dry coal outfeed from the dryer is suddenly stopped.

2.5.3 Coal Dust Explosion Protection

1. Preferably locate coal screening, crushing, and cleaning processes producing dry coal dust in openstructures. If not possible, provide buildings or rooms within buildings housing these type operations withexplosion venting in accordance with Data Sheet 7-76, Prevention and Mitigation of Combustible DustExplosions and Fires, and Data Sheet 1-44, Damage-Limiting Construction.

2. Provide thermal dryers which produce coal dust clouds as part of or incidental to the process withemergency explosion venting, directed to outdoors. Base design Data Sheet 7-76, Prevention and Mitigationof Combustible Dust Explosions and Fires.

Fig. 40. Sketch of recommended placement of deluge water spray systems for constriction deck and cyclones.



3. Air aspirate all indoor equipment handling dry coal dust (such as conveyor, housings, classifiers, etc.)Alternatively, totally enclose and operate this equipment at a negative pressure relative to the environmentto minimize release of dust into the building.

4. Provide collection intakes at all points where dust can be liberated, such as at unloading stations, conveyortransfer points, at classification equipment, in silo or bin galleries and tunnels, and in truck or rail loadoutstations.

5. Design and vent dust collectors in accordance with Data Sheet 7-73, Dust Collectors and CollectionSystems, and 7-76, Prevention and Mitigation of Combustible Dust Explosions and Fires. Locate dust col-lectors outdoors whenever possible and provide collectors with emergency explosion venting. If locatedindoors, direct explosion venting to the outdoors by the shortest route possible using strong ductwork.

6. Do not reintroduce collected dust back into the coal stream within the plant except where this is an integralpart of the process, such as in a fluidized thermal dryer operation. Reintroduce captured coal fines only atrail or truck loading stations.

7. Ensure that housekeeping and maintenance of equipment are of the highest order in coal handling areas.Promptly remove spills of coal or accumulations of coal fines, preferably by vacuuming or water washing.

2.5.4 Methane Explosion Protection

1. For locations processing coal known (or suspected) to be high in combustible gas content, provide thefollowing protection for below grade or confined storage locations, such as silo interiors:

a) Combustible gas detectors designed to sound an alarm in a constantly attended location when theconcentration of methane in air exceeds 25% of the lower explosive limit.

b) Continuous mechanical ventilation designed to exhaust liberated gases to atmosphere. Design venti-lation rate to keep the concentration below 25% of the lower explosive limit of the gas or gas mixture.Arrange an alarm to sound in a constantly attended area should ventilation be shut off.

2.5.5 Ignition source control

1. Design electrical equipment in coal processing buildings for Class II, Division 1 or 2, in accordance withData Sheet 5-1, Electrical Equipment in Hazardous (Classified) Locations. Special electrical equipment isnot needed in the following areas:

a) Processing areas where coal is sufficiently wet to prevent airborne dust.

b) Plant areas, such as control rooms, electrical equipment rooms (i.e., motor control centers, transformervaults, etc.), and other rooms which are cutoff and ventilated and/or pressurized to prevent interioraccumulations of coal dust.

2. Design electrical equipment in areas prone to methane gas accumulation for Class I Division 1 inaccordance with Data Sheet 5-1, Electrical Equipment in Hazardous (Classified) Locations.

3. Monitor carbon monoxide (CO) gas formation, which is an early indicator of internal heating which couldlead to spontaneous combustion, using FM Approved combustible gas detectors inside long term coal stor-age silos, bins, and bunkers. Long term is defined as storage in residence more than one month.

4. Refer to Data Sheet 8-10, Coal and Charcoal Storage, for additional recommendations concerning controlof spontaneous heating of coal in storage bins.

5. Do not use space heating equipment in dry coal dust areas that have open flames or any exposed surfaceat temperatures above 340°F (171°C).

6. Do not permit railroad locomotives or other vehicles which could ignite a dust cloud to operate within caror truck loading/unloading buildings while a coal dust cloud is present. Provide Class II Group G front endloaders and lift trucks routinely present in areas with coal dust clouds occupancies as described in Data Sheet7-39, Industrial Trucks.

7. Preferably, restrict hot work from areas with coal dusts, potential methane accumulations, or near or overplastic equipment. When needed, use a formal hot work permit system. Determine the presence of methaneor other combustible gases using a portable gas detector and eliminate the gas source or accumulation priorto hot work.



2.5.6 Protection of Coal Silos

1. Provide coal silos with FM Approved products of combustion detection to provide early warning of spon-taneous combustion or hot spots introduced by burning coal. Carbon monoxide (CO) detection provides thebest early warning although CO/CO2 ratio analysis has also proven effective. Light sensors are subject to coaldust obscuration. Smoke detection might work if placed in exhaust ventilation duct work away from coal dusts.Also provide coal silos with methane detection, designed to sound an alarm at 25% of the Lower FlammabilityLimit (LFL). All detectors should alarm in a continuously occupied area. When detectors alarm, commenceappropriate emergency action, as defined below.

2. Provide coal silos with explosion venting, or continuously purge the system with an inert gas, based onguidelines in Data Sheet 7-76, Prevention and Mitigation of Combustible Dust Explosions and Fires.

3. Develop in advance and document an effective emergency response to a coal silo fire. Train and equipemergency response personnel to respond to a concealed, hard-to-control fire with explosion potential.

4. Consider the use of carbon dioxide (CO2) as fire suppressant for deep seated coal silo fires rather thanwater or nitrogen. Water can cause subsequent steam explosions. Nitrogen will not effectively settle downinto the silo and is expensive. Calculate the amount of CO2 needed for the given silo or silos in advance andprovide sufficient supply and pressure to fill the entire silo volume in 10 minutes. Permanently pipe the CO2

from a storage tank to the top of the silo. Arrange the system for manual or automatic operation. Base dura-tion of supply on time to draw out burning coal while maintaining an inert blanket of gas on the interior.

3.0 SUPPORT FOR RECOMMENDATIONS

Mining is defined as the surface or underground extraction of minerals or fossil materials from the earth.Examples of surface mining are open pit, strip, hydraulic, placer, quarry, and dredge. Examples of under-ground mining are room and pillar, sublevel stopping, subcaving, and longwall. Refer to Appendix A, Glossaryof Terms, for definitions of common terms of this industry.

Fig. 41. Flow diagram of mining and mineral processing activities from exploration to product sales.



4.0 REFERENCES

4.1 FM Global

Data Sheet 1-0, Safeguards During ConstructionData Sheet 1-1, Firesafe Building Construction and MaterialsData Sheet 1-2, EarthquakesData Sheet 1-6, Cooling TowersData Sheet 1-29, Wind DesignData Sheet 1-9, Roof AnchorageData Sheet 1-13, ChimneysData Sheet 1-25, Process Tanks and SilosData Sheet 1-40, FloodData Sheet 1-44, Damage Limiting ConstructionData Sheet 1-54, Roof Loads for New ConstructionData Sheet 1-57, Plastics in ConstructionData Sheet 1-62, CranesData Sheet 2-0, Installation of Automatic SprinklersData Sheet 2-81, Fire Safety Inspections and Sprinkler System MaintenanceData Sheet 3-2, Water Tanks for Fire ProtectionData Sheet 3-7, Fire Protection PumpsData Sheet 3-11, Pressure Reducing Valves for Fire Protection ServiceData Sheet 3-26, Fire Protection Water Demand for Non-Storage Sprinklered PropertiesData Sheet 4-0, Special Protection SystemsData Sheet 4-1N, Water Spray Fixed SystemsData Sheet 4-4N, Standpipe and Hose SystemsData Sheet 4-7N, Low Expansion Foam SystemsData Sheet 4-10, Dry Chemical SystemsData Sheet 4-11N, Carbon Dioxide Extinguishing SystemsData Sheet 5-1, Electrical Equipment for Hazardous (Classified) LocationsData Sheet 5-3/13-2, Hydroelectric Power PlantsData Sheet 5-4, TransformersData Sheet 5-7, National Electrical CodeData Sheet 5-11, Lightning Surge Protection for Electrical SystemsData Sheet 5-13, Synchronous MotorsData Sheet 5-17, Large Electric MotorsData Sheet 5-18, Protection of Electrical EquipmentData Sheet 5-19, Switchgear and Circuit BreakersData Sheet 5-20, Electrical TestingData Sheet 5-23, Emergency and Standby Power SystemsData Sheet 5-24, Miscellaneous Electrical EquipmentData Sheet 5-31, Cables and Bus BarsData Sheet 5-32, Electronic Data Processing SystemsData Sheet 5-49, Gas and Vapor Detectors and Analysis SystemsData Sheet 6 Series, Boiler and Industrial Heating EquipmentData Sheet 6-2, Pulverized Coal-Fired FurnacesData Sheet 6-4, Oil- and Gas-Fired Single-Burner BoilersData Sheet 6-5, Oil- or Gas-Fired Multiple Burner BoilersData Sheet 6-7, Fluidized Bed Combustors and BoilersData Sheet 6-9, Industrial Ovens and DryersData Sheet 6-10, Process FurnacesData Sheet 6-11, Fume IncineratorsData Sheet 6-13, Waste Fuel-Fired BoilersData Sheet 6-17, Rotary Kilns and DryersData Sheet 6-24, Coal Pulverizers and Pulverizing SystemsData Sheet 7-6, Heated Plastic and Plastic Lined TanksData Sheet 7-11, Belt ConveyorsData Sheet 7-13, Mechanical RefrigerationData Sheet 7-14, Fire + Explosion Protection for Flammable Liquid, Flammable Gas, + Liquefied Flammable



Gas Processing Equipment + Supporting StructuresData Sheet 7-28,Energetic MaterialsData Sheet 7-29, Flammable Liquid Storage in Portable ContainersData Sheet 7-32, Flammable Liquid OperationsData Sheet 7-35, Air Separation ProcessesData Sheet 7-37, Cutting OilsData Sheet 7-39, Industrial TrucksData Sheet 7-40, Heavy Duty Mobile EquipmentData Sheet 7-43, Loss Prevention in Chemical PlantsData Sheet 7-45, Instrumentation and Control in Safety ApplicationsData Sheet 7-48, Disposal of Waste MaterialsData Sheet 7-50, Compressed Gases in CylindersData Sheet 7-51, AcetyleneData Sheet 7-52, OxygenData Sheet 7-55, Liquefied Petroleum GasData Sheet 7-56, MAPP Industrial GasData Sheet 7-64/13-28, Aluminum IndustryData Sheet 7-73, Dust Collectors and Collection SystemsData Sheet 7-76, Prevention and Mitigation of Combustible Dust Explosions and FiresData Sheet 7-78, Industrial Exhaust systemsData Sheet 7-83, Drainage Systems for Flammable LiquidsData Sheet 7-88, Storage Tanks for Flammable and Combustible LiquidsData sheet 7-89, Ammonium Nitrate and Mixed Fertilizers Containing Ammonium NitrateData Sheet 7-95, CompressorsData Sheet 7-98, Hydraulic FluidsData Sheet 7-99, Heat Transfer by Organic and Synthetic FluidsData Sheet 8-10, Coal and Charcoal StorageData Sheet 9-7/17-5, Property ConservationData Sheet 9-18/17-18, Prevention of Freeze-UpsData Sheet 10-3, Hot Work ManagementData Sheet 12-61, Mechanical RefrigerationData Sheet 13-6, Flywheels and PulleysData Sheet 13-7, GearsData Sheet 13-9, Steam TurbinesData Sheet 13-17, Gas TurbinesData Sheet 13-24, Fans and BlowersData Sheet 13-26, Internal Combustion EnginesData Sheet 17-1, Nondestructive Examination

APPENDIX A GLOSSARY OF TERMS

A.1 Mineral and Ore Terms

Coal: a naturally occurring organic hard carbon rock or softer material formed by pressures within the earth’scrust from layered organic matter. A material is considered a coal product if it is at least 40% carbonaceous.Four predominate coal types — lignite, sub-bituminous, bituminous, and anthracite — are ranked accord-ing to hardness, volatility, and amount of carbon. Coal is characterized by its combustibility and by-product for-mation of combustible or explosive materials such as methane, carbon dioxide, and dusts.

Anthracite Coal: a black lustrous hard coal containing a high percentage of fixed carbon and a percentageof volatile material between 2 and 8%.

Bituminous Coal: A soft coal that ranks between anthracite and sub-bituminous coals. It contains morethan 14% volatile matter and has a calorific value in excess of 11,500 BTU/lb (26.7 Mj/Kg).

Sub-bituminous Coal: Soft coal ranking between lignite and bituminous with high volatile content. It hasa calorific value between 8,300 BTU/lb and 11,500 BTU/lb (19.3 Mj/Kg and 26.7 Mj/Kg). It is Classified asA, B, and C grades depending on calorific value.



Lignite Coal: a brownish-black very soft coal in which the alteration of vegetal matter has proceeded furtherthan peat but not as far as sub-bituminous. Lignite coal is high in moisture and volatility and has a calorificvalue less than 8,300 BTU/lb (19.3 Mj/Kg).

Concentrate: the valuable material produced from an ore by a separating or concentrating process

Dore (Pr: ‘‘Door-Aay’’): a silver-gold alloy commonly formed at a gold mine site in bullion (bar) form. Thedore bar is sent offsite for separation and purification of the two metals. Dore is typically 70% gold and 30%silver although these percentages can vary widely.

Footwall: wall or rock under an ore deposit

Fossil material: carbon based (organic) materials that were created in the earth’s crust due to fossil decay,deposition, and pressure forces. Typical fossil materials that are exploited by mining are coal, petroleumliquids, tar sands, natural gas and gas liquids, gilsonite, and oil shale.

Gangue: undesirable waste rock mined with valuable minerals in an ore body. Gangue is disposed of onmine dump piles, as tailings, or used as fill for exhausted mine areas or it may be used for road building orother construction purposes.

Gob: broken, caved, and mined-out (and often abandoned) portion of an ore deposit. Coal gobs are sourcesof spontaneous heating.

Hard Rock: hard metallic ores (i.e., gold, copper, zinc, lead), non-metal aggregates (i.e., gravel), or structuralminerals (i.e., granite, marble). Hard rock mining is the extraction and processing of hard rock materials.Coal and many non-metal materials such as salt, trona, and potash are considered ‘‘soft rock’’ materials andtheir extraction soft rock mining.

High Sulfide Content (HSC) Ores: ore deposits containing high concentrations of pyritic or iron sulfidecompounds. HSC ores are subject to spontaneous heating and their dusts, when released and ignited byconventional blasting, can explode violently. A sulfides content in excess of approximately 28% should beconsidered explosive prone.

Lode: mineral deposit in solid rock.

Matrix: rock or gangue material containing ore minerals.

Metal mineral: belonging to the class of inorganic metal compounds which include gold, silver, copper,tungsten, molybdenum, vanadium, tin, nickel, and lead. Some metals are found in pure metallic form(e.g., gold, silver, tin, and copper) but most are found as oxide or sulfide ores in large but relatively low gradequantities that must be further processed to recover the pure metal.

Mineral: a naturally formed inorganic substance occurring in the earth’s crust and having a consistent and dis-tinctive set of physical properties and a composition that can be expressed by a chemical formula. Whilethe term ‘‘mineral’’ sometimes is used in reference to coal and other organic fossil based materials, mineralin this document is used only for metal or non-metal compounds and not fossil materials.

Muck: mineral ore or waste rock that has been broken by blasting.

Non-Metal mineral: structural and industrial minerals. These non-fuel inorganic materials do not become met-als by metallurgical processing. They are used as mined or are chemically processed into other non-metalcompounds. Examples of industrial non-metallics are trona, potash, asbestos, sulfur, barite, limestone,abrasives, and salt. Examples of structural non-metallics are quarry products such as sandstone, marble,granite and rock (sand and gravel) aggregates. Most gemstones fall in the non-metals mineral category.Gemstones commonly occur in placer deposits.

Nugget: a small mass of native precious metal.

Ore: a mixture of valuable mineral and gangue waste rock

Orebody: natural concentration of valuable minerals that can be extracted and sold.

Overburden: undesirable, valueless material covering a valuable ore or coal deposit which has to be removed,(usually by surface mining) to access the valuable deposits.

Pipe: vertical, narrow orebody usually formed in the throat of an ancient volcano or magma chute. Diamondsare often found in pipes.



Shoot: concentration of minerals; that part of a vein or zone that carries the valuable ore grades.

Vein: a well-defined tabular mineralized zone, which may or may not contain ore bodies.

Wash: barren rock or mineralized material that does not have enough value to be classified as ore

A.2 Mining Terms

Aerial ropeway/cableway/tramway: a system of cables or wire ropes suspended from towers or pylons fromwhich hang cages, buckets, or baskets for hoisting or transferring ore (and occasionally personnel) overrough, steep terrain.

Adit/Drift/Entry: a horizontal entrance in a mine used to transport equipment and personnel and remove ore.Drifts and adits are metal mine terms and entry is a coal term. An adit that is continuous through a mountainand has two portals is a tunnel.

Afterblast: the after effects of a combustion explosion of methane underground where oxygen and steamform as by-products of the explosion. The steam condenses to water, forming a partial vacuum which causesan in-rush of air pressure into the mine.

Afterdamp (aftergases): mixture of gases remaining in a mine after a fire or explosion of combustible gases.These gases, consisting primarily of hydrogen, carbon dioxide, and nitrogen inert the air and may preventeffective emergency response.

Air blast: pressure wave of air passing down tunnels in a piston-like effect. It is caused by a sudden rockfall (see burst or rock burst) or other disturbance such as a remote explosives discharge which pushes theair at great force. The air burst can extend for thousands of feet (meters), causing pressure effects damage.An air blast can also disturb combustible dusts (such as coal or HSC ores), which could ignite and cause asecondary explosion. Air is eventually discharged from the mine.

Air Blasting: method of blasting in which compressed air at very high pressure is piped to a steel shell in ashot hole and discharged.

Air Shaft: shaft used for ventilating mines, downcast when delivering fresh air into the mine and upcast whenexhausting air from the mine to the surface.

ANFO: mixture of explosive grade ammonium nitrate (AN) and diesel fuel oil (FO) commonly used in miningexcavation blasting due to its low cost, inherent stability, and ease of handling.

Back (Roof): interior exposed rock ceiling of an underground tunnel, slope, drift, or adit.

Bulkhead: timber or concrete dam which holds air, tailings, or water in place

Burst: sudden and violent release of energy and pressure contained in a stressed rock (see air burst androck burst)

Cage: personnel or equipment elevator located in a shaft.

Cap: uppermost heavy crosspiece timber in a timber set, supported on timber columns or posts. (See TimberSets)

Cave-in: partial or complete collapse of a mine working

Chute: opening underground through which ore can gravity flow from an active upper mining level to a lowerhaulageway level, usually used to load ore into mobile equipment or conveyors for transport from the mine.Chutes can be constructed of natural rock or be wood lined.

Collar: surface at the top of and surrounding the throat of a vertical shaft.

Colliery: underground coal mine

Crib: system of timbering in which the timbers are laid one upon the other to form a rectangular opening inthe center, often used to line ore chutes and ore passes

Cross-cut: horizontal level driven at an angle to the strike of a vein

Drift: see adit

Entry: coal mining term for adit



Face: the working area where desired ore is present

Fiery Mine: mine (usually coal) that is already burning or prone to burning due to coal volatility. Often usedto describe gassy mines that may or may not be already burning. Often used by regulatory agencies to definecode requirements thresholds.

Firedamp: methane gas. Methane is an explosive gas common in coal mines and occasionally found in metalmines.

Gassy Mine: mine, usually coal, which may form (or already contains) pockets of combustible gases suchas methane or carbon monoxide. Regulatory agencies often use this term to define general level of hazardfor code compliance. Some metal and non-metal mines may be located within or near coal or undergroundgas deposits which might produce a regulatory classification as gassy.

Fig. 42. Ventilation system using shafts for a deep metal mine.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Grizzly: a rugged fixed or mobile screen or series of closely spaced parallel steel rods or rollers use to roughsize or scalp ore of a comparatively large size. Often used prior to primary crushers to separate bouldersfrom smaller rock. Grizzlies are often located underground below chutes ahead of ore bins. A mantle is a typeof grizzly.

Grout: a filling agent injected by pressure into loose and broken rock or ground to stabilize the area

Gunite: an air-blown mortar consisting of one part cement and three to five parts sand, used for coatingsurfaces to prevent rock fall.

Hard Rock Mining: applies to mining involving very hard mineral deposits such as metal ores or non-metalstructural materials such as granite or marble, as differentiated from softer materials such as coal, trona or pot-ash. Hard rock mining often involves frequent blasting of deposits to loosen ore and requires significantlymore downstream crushing and grinding to obtain desired particle size. Coal and soft non-metallics areremoved faster and easier by continuous grinding, scraping, water pressure, or augering devices.

Haulageway: horizontal underground passageway used primarily to move ore or waste by self propelled orrail mounted mobile equipment.

Head Frame (a/k/a Hoist Frame or Gallows Frame): structure positioned over a vertical or near vertical shaftfor transporting materials, personnel, waste, and ore to and from an underground mine. Head frames (andassociated hoisting equipment) are usually located aboveground but can also be located underground. Olderhead frames may be constructed of wood timbers. Newer head frames are usually of steel frame construc-tion with metal cladding or are built into hard rock structures underground. Pulleys (sheave wheels) and wireropes are usually provided at the top of the head frame. Drive machinery and motors are usually located innearby hoist rooms. (See hoist).

Hoist: a machine, usually driven by one or more large, often synchronous, electric motors, which is used toraise and lower one or more conveyances in a mine shaft using wire ropes. Mine hoists are categorizedas either drum or friction types. Drum hoists have one end of the wire rope or ropes anchored to the drum.The wire ropes are wound and unwound from the drum to move the conveyances. Friction (aka Koepe) hoistsraise and lower the conveyance by passing the hoisting or head ropes over a wheel and driving the ropes bymeans of friction. Hoisting equipment is located in buildings or rooms near hoist frames.

Inby (Inbyside): in the direction of the face of the mine or further into the mine. Opposite of outby.

Fig. 43. Drawing of a typical underground mine operation showing chutes, grizzlies, cribs, and typical ground supportmethods. (Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



In-Situ (in place) (Solution Mining): method of mining minerals that can be recovered by liquid dissolutionat the mineral source inside the mine. Also called selective chemical extraction. An example of in-situ miningis that involving sulfur or salt deposits. Hot water is pumped into the deposit to dissolve the desired material.The pregnant solution is pumped to the surface as a slurry where it is further processed.

Lagging: planks or timbers placed around or behind timber sets to keep rock material from falling from thewalls or the back of the tunnel. Wood lagging can significantly contribute to combustible loading and firespread. (See Timber Sets)

Lateral: a secondary or tertiary horizontal passageway, usually parallel to a haulageway. It is used for utilitiessuch as power cables, piping, or for ventilation air.

Level: horizontal underground working (usually a series of interconnected tunnels and passageways) thatis connected to a shaft. A level forms the basis for excavation of the ore above or below. A deep mine will haveseveral working levels.

Mantle: See Grizzly

Mining: extracting, recovering, and exploiting minerals or coal from their natural environment and transportingthem to the point of processing or final use.

Outby (Outbyside): direction away from the face of the mine or toward the outside of the mine. Opposite ofinby.

Portal: surface entrance into a horizontal mine tunnel or adit.

Pillar: unmined portion of an ore deposit which provides temporary support during mining of adjacent areasor rooms. An ore pillar is eventually mined for valuable minerals during a retreating process during whichthe mine back is allowed to collapse and fill the mined out area. Pillar is also used to describe the two verticalsupports of a timber set or other material such as concrete, used to support a mine back.

Fig. 44. Head frame structure at modern non-metal mine. Hoist house is to the left.(Courtesy of Elf Aquitaine, TGI Soda, Grainger WYO)



Fig. 45. Close up view of head frame in Figure 44, showing wire ropes from adjacent hoist room, sheave wheel attop, and structural supports. (Courtesy of Elf Aquitaine, TGI Soda, Grainger WYO)



Fig. 46. Multi-rope, friction-sheave hoisting system, mounted in headframe.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Prop/Stull: single timber post used to support loose rocks or a low outcropping of the mine back. Props (coalmine term) and stulls (metal mine term) are commonly used in stopes. Props can give early visual warningof tunnel back failure by bending and cracking.

Raise: excavation of restricted cross section driven upward, either vertically or at a steep angle, from onelevel in a mine to another.

Rock Burst: violent release of energy contained in highly stressed rock when the rock formation suddenly col-lapses, expelling material and pressure out into an adit or tunnel. Rock bursts can cause high pressure waves(piston forces) through tunnels for hundreds or thousands of feet. Rock bursts can occur in coal and metalmines. Coal bursts can be caused by methane gas pockets within coal deposits. Metal rock bursts are causedby unstable geological structures and faults within the mine and can be initiated by earthquakes or poor mineback support.

Rockbolt: steel bolt with an expansion wedge at one end inserted into a drill hole. One of several methodsto support mine backs where rock is unstable.

Roof: overhead of the mine tunnel (commonly called the back)

Shaft: vertical or near vertical opening into the earth used to extract waste and ore from the mine, for personneland equipment entry, for utility cables and pipes, and as a conduit for mine ventilation. Shafts can be manythousands of feet (meters) deep and be lined with wood or noncombustible materials.

Shaft Station (Station): enlargement of a shaft (or a room) made for staging of equipment delivered to andfrom the shaft and for personnel entry into drifts at that elevation. Several stations are normal along the verticallength of a typical shaft.

Shotcrete: generic term used for hydraulically pressure spraying a cementitious material such as gunite onwalls and other surfaces.

Skip: self dumping bucket in which ore or waste rock is raised through a vertical shaft to the surface.

Slope: inclined or declined opening into the mine, usually passing through undesirable waste materials toreach a valuable ore deposit.

Fig. 47. Typical hoists found in mining operations.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 48. Isometric layout of an underground mine showing levels and mining terms.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 49. Plan and cross section views of typical shafts and levels of an underground mine.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 50. Drawing of underground metal mine supported by ore pillars. Shown is a room and pillar mining method of aninclined ore body. (Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 51. Drawing of a hardrock mine featuring concrete pillars which temporarily support a longwall mining zone.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Stinkdamp: term for hydrogen sulfide gas formed as a by-product of burning coal. Hydrogen sulfide is anexplosive gas.

Stope: short branch from a slope or decline tunnel where ore is mined. Stopes commonly follow ore seamsand are often on an incline to facilitate gravity flow of mined ore. Stopes are commonly layered one abovethe other in a step-like formation.

Stopping: barrier installed in an underground tunnel, drift, adit, or entry to control smoke, fire, gas, water,or ventilation. A fire door is a form of mine stopping as is a bulkhead.

Sump: lowest part of the mine where water is collected and removed by pumping, commonly at the bottomof a vertical hoist shaft.

Surface mining: extraction of minerals or coal aboveground from the surface of the earth. Surface miningis conducted where ore or coal reserves are close to the surface by one of the following methods:

Open Pit (Open Cut): open extraction for removing ore near the surface or where a high concentrationof minerals in a deep body are more economical to access from the surface. Bench, strip and quarry minesare types of open pit. Large man-made open pits generally have circular benches sloping inward intothe pit for truck and heavy equipment access. The larger open pits can be miles (kilometers) across andthousands of feet (meters) deep. Moveable primary crushers and conveying systems may be presentinside the pit. Generally, large open pits are not refilled once mining operations cease. Instead, gangue(waste) is separated from the desired ore in concentrator mills and placed on large tailings piles or stacks.

Strip: open cut surface mining of coal. Usually an overburden of a 100 ft (30 m) or less is removed bydraglines to expose a relatively thin layer of coal which is then extracted with large front end loaders intotrucks or conveyor systems. Strip mines can extend for miles across open country. Overburden is replacedafter the coal is removed and the terrain is usually restored.

Quarry: surface mining of structural rock such as sandstone, granite, slate, and marble. Mining is doneby high pressure water or special saws that cut the desired material into blocks. Aggregate (sand and

Fig. 52. Examples of rock bolts for ground support.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



gravel) extraction is also usually classified as quarry mining. This is a suitable technique for bench layereddeposits.

Placer: mining technique using panning, sluicing, hydraulic, or dredging of valuable metals such as goldand tin or gemstones from an alluvial sand or gravel deposit. It is used where a ready supply of wateris available and where high grade ore, pure metal or gemstones are present on or near the surface.Hydraulic methods, using high pressure water, are used to remove gravel overburden. Floating dredgesor moveable processing plants remove ore from under shallow water (such as in river or lakes) and insome cases contain on board concentration equipment. Placer mining is environmentally disturbing andreclaim of disturbed overburden is usually required.

Glory Hole: vertical hole accessed from the surface but with a narrow throat at the bottom which feedsmined ore downward into an underground storage area where it is transported to the surface by othermeans.

Tipple: structure used to load ore or coal into trucks or rail cars for haulage to a remote conveying or tram sys-tem or directly to a concentrator mill. Also used for dumping ore into crusher facilities. A device is used totip mine ore cars onto their sides. The ore falls by gravity down a chute into the crusher chute or waiting haul-age vehicle, staged at a lower level. The tipping device may feature a hydraulic fluid system. Older tipplesare almost always of wood frame construction; newer ones usually feature steel or concrete construction.Older tipples may connect to a wood frame trestle that supports a rail line for ore cars arriving from the mine.This may create a significant continuity of combustible loading, especially if the mine has wood timber setsnear the portal.

Timber Set: Mine back support structure that is comprised of two wood timber uprights (pillars) and one woodtimber cross beam (cap). Timber sets are spaced several feet (meters) apart and may or may not have woodlagging next to the mine back or walls as additional support or protection against falling materials. Structuralsteel and reinforced concrete sets are also used. Wood timbers have historically been preferred by miners as

Fig. 53. Cross section view of a typical wood lined vertical shaft.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



they give advanced warning and long term trending of mine collapse by noise, cracking, and bending.

Fig. 54. Photograph of large open pit mine.

Fig. 55. Ore mining of caved pit wall.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Tunnel: a generic term for a horizontal (or nearly horizontal) opening into the earth for ore extraction, personneland equipment entry, or ventilation purposes. Strictly speaking, a tunnel has openings at both ends. Adits,drifts, entries and slopes are all forms of tunnels, but they usually have only one entrance.

Underground Mining: removal of minerals from beneath the surface of the earth. Underground mining isusually conducted where ore reserves are not close to the surface or do not lend themselves to open pit typeoperations. There are many underground mining methods including the following:

Self Supported: mining method in geologically firm ground which needs no additional ground support.

Room-and-pillar: mining method where large columns (pillars) of valuable ore are purposely left in placeto support the mine back, leaving large open rooms around the supports. After a room has been mined,the pillars are mined and the mine collapses inwardly, filling the room.

Stoping: act of excavating ore in a series of steps.

Sublevel Stoping: stoping method in which the ore is excavated in open stopes, retreating from one endto the other. The ore is dropped into chutes to lower level haulage ways.

Shrinkage Stoping: stoping method in which the ore is removed from vertical overheads and allowed tofall onto the floor of the stope. The buildup of ore on the floor helps support the walls.

Cut-and-fill stoping: stoping method in which the ore is excavated by successive flat or incline slices inan upward direction from the level. It is similar to shrinkage stoping. However, after each slice is blasteddown, all broken ore is removed. The stope is filled with waste almost up to the roof (back) of the stopebefore the next slice is blasted out. This leaves room on the top of the waste on which to stand and work.

Open Stope: stoping in which no regular artificial method of ground support is used except occasionallyindividual stulls (props) or cribs which hold localized patches of insecure ground. The walls and back of

Fig. 56. Schematic view of large open pit copper mine and mills.(Bingham Canyon Mine, Courtesy of Rio Tinto Mining, Kennecott Copper, Utah)



Fig. 57. Photograph of surface strip mining of coal. Dragline is used for overburden removal.

Fig. 58. Photo of a floating dredge in a placer gold mining operation.



an open stope are self supporting. Open stopes are used where the ground is firm and stable.

Longwall: mechanized mining system used for layered deposits of coal and soft non-metallics such assalt, potash and trona. Longwall mining features wide cuts along a long face up to 3000 ft (914 m) longand intentional caving and hydraulic support systems. One large piece of mobile excavating equipment withmoving conveyor systems is used along a single mining face. The longwall excavator has hydraulic lift-ers that hold the back of the mine in place until the coal along the seam is cut and removed. As the machinemoves laterally along the seam, the back of the mine is allowed to collapse and fill the mined area asit is released from hydraulic support.

Shortwall: similar to longwall but features multiple excavators along the longwall to avoid complete lossof production if a single unit is out of service. It is not a commonly used process.

Fig. 59. Drawing of a hydraulicking operation in a gold placer bed.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 60a. Section view of a single timber set used underground for ground support.



Sublevel caving: stoping method in which relatively thin layers of ore collapse (cave) by successivelyundermining small panels. Chute raises connect a lower level haulage road to the caved area. The orefalls down the chutes and is hauled away.

Block caving: mass mining system where the ore extraction depends on gravity. By removing a thinhorizontal layer at the mining level of the ore column, the vertical support of the ore column above isremoved and the ore caves by gravity. As broken ore is removed, the ore above continues to break andcave. Block caving is no longer widely used.

Panel caving: systematic and safe block caving technique which features smaller areas of caving.

Walls: sides of a tunnel, drift, adit, or entry.

Fig. 60b. Isometric view of a series of timber sets in an underground tunnel.

Fig. 60c. Section view of a timber set with wood plank lagging

Fig. 60d. Isometric view of a series of timber sets with wood plank lagging



Whitedamp: carbon monoxide (CO) formed by spontaneous combustion or slow oxidation of coal or other car-bon based materials. Carbon monoxide is an explosive gas common to coal mines. It also can be formedby combustion in wood timber sets or in discarded waste organic materials in metal mines.

Winze: shaft-like opening sunk from a level in a mine to develop, dewater, or ventilate an ore zone. Similarto a raise but usually used for auxiliary utility, rather than ore extraction.

A.3 Ore Processing and Refining Terms

A-Frame: storage building for crushed or concentrated ore or coal. Usually has an overhead rubber belt galleryto feed piles and an underpile reclaim tunnel featuring hydraulic systems and rubber belts.

Acid plant: chemical processing facility for converting sulfur oxides (created as undesirable by-product gasesin smelters and oxidation/reduction processes) to a marketable sulfuric acid and clean air that can bedischarged to the environment. Acid plants and their associated air and chemical handling systems are usedprimarily as an emission control system but also usually produce acid for plant processes. Excess acid issold. An acid plant features upstream mist and dust precipitators, absorbers, converters, drying towers, heatexchangers, and strippers. Acid plants often have large fibre reinforced plastic (FRP) duct systems or othercombustible construction (older facilities may have wood duct systems) that feed a high stack or chimneywhich may be plastic lined. Usually a plant cannot operate if the acid plant is shutdown, although factors suchas production reliance on by-product acid, regulatory laws, prevailing winds, and emission stack height allplay a role in permission to operate a metal refinery without acid recovery.

Fig. 61. Room-and-pillar mining of a flat orebody.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 62. Room-and-pillar mining of an inclined orebody.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 63. Sublevel stoping with large hole drilling and blasting.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 64. Sublevel stoping with ring drilling as the primary means of breaking ore.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 65. Shrinkage stoping in a large vertical orebody.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Activator (Activity Reagent): liquid chemical, used in flotation processes, which is added to a pulp (ore slurry)to increase the floatability of the mineral or to refloat a depressed (sunk) mineral. Also see reagent.

Aeration: introduction of air into pulp in a flotation cell in order to form air bubbles on which mineral valuescan be collected.

Agglomeration: beneficiation (flotation) process based on the adhesion of pulp particles to water. Looselybonded associations of particles and bubbles are formed that are heavier than water; flowing film gravity sepa-ration is used to separate the agglomerated material from the nonagglomerated materials. Agglomeration

Fig. 66. Cut-and-fill mining in a large vertical orebody.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 67. General view of an open stoping mine.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



is also used to prepare certain types of very fine oxide ores for heap leaching. In the process, fine ore isheated in a kiln in the presence of weak sulfuric acid to form soft agglomerized pebbles. These are cooledand layered onto the heap leach pad where they allow cyanide liquid to more easily penterate the pilebecause of the voids created around the soft pebbles. Agglomeration is also a metallurgical refining processfor forming balls, briquettes, nodules, flakes, or other size shaped particles from loose, usually fine incoherentparticles.

Autogenous mill: rotating cylinder using ore impact to reduce particle size. Artificial media such as steel balls,pebbles, or rods are not used in fully autogenous mills. A form of ore comminution. (See semi-autogenous[SAG] mills)

Ball Mill: A rotating grinding cylinder using steel balls as the grinding media. A form of ore comminution.

Beneficiation: non-metallurgical refining (concentration or dressing) of metal ore or coal to separate wastematerial from valuable minerals. The most common beneficiation process is froth flotation whereby fine oreor coal is captured on bubbles or froth created by agitated reagents in special cells, tanks or troughs.

Bio-Leaching: process for recovering metals from low-grade ores by dissolving them in solution, aided bybacterial action.

Carbon-In-Pulp (CIP) Process: method of recovering gold and silver from pregnant cyanide solutions (suchas from a heap leaching operation) by adsorbing the desired metals onto activated carbon. The metal issubsequently removed from the carbon by weak cyanide solution cleansing and electrowinning.

Fig. 68. Longwall mining of coal deposit.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Clarification: process of cleaning ‘‘dirty’’ water by removing suspended solid materials.

Classification: physically separating particles into various sizes, derivatives, and shapes using screens andcyclones (such as hydrocyclones) or by settling in tanks, thickeners, or ponds.

Coal Preparation Plant: processing plant that cleans, washes and dries coal. A coal preparation plant mayhave beneficiation processes which use flammable reagents, thermal oil heated or fuel fired driers, rubber beltconveyors, grouped plastic cables, plastic piping, hydraulic and lubrication fluid systems, and coal in processincluding explosive coal dusts.

Fig. 69. Sublevel caving in a large and steeply dipping orebody.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 70. Block caving in a massive orebody, showing a conventional mining layout.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 71. Photo of A-Frame building for bulk coal storage, with incline, totally enclosedconveyor belt delivery and reclaim system.



Column Flotation: milling process in a tall cylindrical column in which valuable minerals are separated bytheir wetability properties.

Comminution: ore or rock particle size reduction by breaking, crushing, and grinding.

Concentration: separating waste material (gangue) from valuable mineral to produce marketable metals. Ben-eficiation and various extractive metallurgical processes, such as smelting, are all forms of concentration.Many mines use several types of concentration processes in series to produce increasingly higher grades ofconcentrate or metal, until the final desired metal content is achieved.

Concentrating Mill (a/k/a ‘‘Mill’’ or ‘‘Concentrator’’): metal/non-metal mineral processing plant used to grindand separate ore into small particles to obtain desired mineral value for further downstream refining and toseparate undesired waste tailings. Mills may contain multiple side-by-side grind circuits. Each grind circuitusually features one or more autogenous, semi-autogenous (SAG), and/or ball and rod mills with associatedhydrocyclones, pumps, piping, and dewatering systems. Following grinding the desired mineral is separatedfrom the gangue by flotation, thickeners, gravity, shaker table, magnetic, or other physical separationprocess. Mill circuits feature extensive rubber lined equipment, plastic screens, rubber conveyor belts,grouped electrical cables with plastic insulation, large hydraulic and lubrication fluid systems, and combus-tible or flammable liquid reagents. In cold climates, grind circuits are housed inside buildings. Newer mill build-ings are of noncombustible construction, although foamed-in-place plastic insulation may be present insidemetal panel sandwich walls or used as protection in areas where corrosive materials are present. Plastic(FRP) light panels in roofs and walls are common. Older mills are of all wood or of metal clad wood frameconstruction. Concentrating facilities in warm climates are usually located outdoors.

Constriction Deck: fluidizing section of a fluidized coal dryer (in a coal preparation plant). It consists of metalgrating or parallel steel bars through which hot air is blown to dry the wet coal.

Crushing: one of several steps in comminution to obtain desired ore particle size. Crushing is achieved bycompressing the ore between two rigid surfaces or by impacting the particle against a massive surface.Crushed rock is usually sized in inches (cm) or larger. Large mines use several levels of crushing (primary,secondary, and even tertiary) to break the ore smaller and smaller before it is pulverized in a grinding mill.

Fig. 72. Photo of gas cooling, scrubbing, and precipitation equipment associated with a typical emission control acid plant.Most of equipment and ducting in this photo are of fiber reinforced plastic construction.



Fig. 73. Photo of a series of typical ball mills in a copper concentrator.

Fig. 74. Cutaway view of the interior of a ball mill.



Typical crushers are jaw, gyratory, Symons (a specialized form of gyratory), cone, stamp mill, and impact(hammermill). Primary crushers may be underground, inside pits, or located at a concentrator plant.

Cyanidation: chemical extraction process which uses a weak sodium or calcium cyanide solution to dissolvemetals from low-grade ore. Used principally for highly oxidized ores and commonly used for gold, silver andcopper recovery. (Also see leaching, lixivation, and heap leaching.) Cyanidation can be carried out in leachtanks (vats), in heap leach piles, or in-situ underground or in open pits. The metal-rich cyanide solution(pregnant liquor) is processed to remove the desired metals, often by a carbon-in-pulp (CIP) or solventextraction recovery process. The separated aqueous stream (raffinate) is recovered and reused.

Dewatering: removal of water from ore concentrate or coal slurries or pulps. Concentrated ore or coal slurriesare often transported to remote metal refining plants by pumping through a slurry pipeline. Once received,water is removed by centrifuging or by filter presses, hydrocyclones, rotacones, or hydroclassifiers. Filterpresses may be vacuum or pressure type and may feature hydraulic fluid systems.

Electrometallurgy: recovery of metal using electric current. Electrothermal and electrolytic are two types ofelectrometallugy. Electrothermal processes use electric current as a heat source and usually fall under pyro-metallurgical processing (which is not further covered in this document). Electrolytic processes use electriccurrent to transport metal ions from anodes and/or electrolytes for deposition on cathodes. Electrolyticprocesses may feature acidic solutions or salt bath. Commonly used for final high purity refining after othermetallurgical processing has been completed. Electrowinning and electro-refining are common forms ofelectrolytic processing.

Electro-refining: electrometallurigical process in which the desired metal in solution is deposited (by the appli-cation of a DC current) onto a cathode that is constructed of the same material as the metal being refined.Starter sheets are used as the cathodes and the deposited metal builds up on these sheets. The undesiredimpurities (slimes) accumulate at the base of the anode in the electrolytic cell or tank. Slimes contain sufficientprecious metal values to be further processed. Electro-refining is commonly used for cobalt, nickel, zinc,

Fig. 75. Photo of a flotation circuit in a copper concentration mill.



and copper. Older cell tanks were constructed of wood. Newer tanks are usually concrete or an expoy resinmixed with concrete. Glass fiber reinforced plastic might be used.

Electrostatic Separation: concentration using variances in electrical conductivity to recover desired materials.Zirconium is commonly recovered by electrostatic methods.

Electrowinning: electrometallurigical process of ‘‘winning’’ a metal from a solution using DC electric currentin cells. Similar to electro-refining, the desired metal as well as the impurities are usually deposited on theanode (a sheet or a sponge) instead of the cathode. The anode is then immersed in an acid solution wherea DC current is applied and deposited metals are dissolved into solution. Once in solution, the metal lowestin electro-motive series (EMS) is preferentially plated onto a cathode, leaving the other metals in solution.The solution is recycled or processed to recover other metals; alternatively, the solution is sent off site, viaeffluent treatment, as waste. The desired metal is recovered from the cathode by mechanical, thermal orchemical methods. Electrowinning is commonly used for gold and silver refining. Electrowinning cells maybe constructed of polypropylene plastic or rubber (or plastic) lined carbon steel. Non-lined stainless steel isbeing used in newer plants to reduce combustibility.

Extractive Metallurgical Processing: chemically altering ore and concentrates to produce marketable-qualitymetals and metallic compounds. Included are pyrometallurgical, electrometallurgical, and hydrometallurgicalprocesses. These types of concentration processes may be located at one large mine site in series or atseparate sites to which several mines produce feedstock concentrates.

Froth Flotation: physiochemical process using reagents and water to selectively separate (by attachment tobubbles) desired materials from undesired materials. Flotation tanks or cells are usually constructed of steelbut may be rubber lined or of plastic construction. Flotation processes are located downstream of grindingcircuits.

Fig. 76. Coal preparation plant using a hillside for gravity flow of product. In the photo, coal is delivered at the top intoraw coal silos, into the beneficiation and cleaning building, and then into the dryer building, center. From the dryerit is conveyed into the clean coal silos for rail shipment.



Gravity Separation: separating (concentrating) solids based on different specific gravities in a fluid medium.Sluice boxes, spiral centrifuges, shaking tables, and sink-float suspensions are examples.

Grinding: a step of comminution (size reduction) to obtain a fine particle or powder after primary or secondarycrushing is completed. Grinding involves a variety of methods. Ball, rod, autogenous, and semiautog-enous (SAG) mills are most common. Grinding, which is done both wet and dry, produces ore of a talc-like con-sistency. The ground ore is usually transported as a water slurry or pulp.

Heap leaching: extractive metallurgical process for recovering metals from mostly weathered, low grade or‘‘spent’’ oxidized ores. Heap leaching is not suitable for sulfide ores. A slightly sloping pad is constructed usingan impervious liner such as plastic or compacted clay (see leach pad) and the crushed, agglomerized, or run-of-mine (ROM) ore is placed on the liner in high and long piles by mobile equipment or moveable conveyors.Piles may be as high as 200 ft (60 m) and thousands of feet (meters) long. They may be constructed acrossvalleys. They feature pyramid type shapes with step benches to prevent failure. A leach solution (com-monly weak sodium cyanide), is sprayed over the ore pile using traditional irrigation type sprinklers, andallowed to percolate down through the ore. Over time (weeks to months) the leach solution dissolves thedesired metal into a pregnant solution which flows by gravity and is captured in lined ponds below the pad.The pregnant solution is pumped or transported by tanker truck to a processing plant where the metal isextracted by chemical processes, such as Carbon-In-Pulp (CIP), or solvent extraction. The aqueous stream(raffinate) recovered in the CIP or extraction process is returned to the process or sent off site as waste efflu-ent. Heap leaching is commonly used for gold, copper, and silver and is very common in the Western UnitedStates, South America, and Australia. Structural failure of a heap pile or liner leakage under a pile can causecontamination of pregnant liquor and environmental damage. Extensive downtime can occur while the heapleach pile is repaired or the liner exposed and patched.

Hydrocyclone: cyclone that separates fine mineral dust from a water slurry, usually downstream of wet grindingmills, in a grind circuit. Usually multiple small hydrocyclones are mounted together in a bank over a single dis-charge tank recovering the output from one grind circuit. The discharge tank, hydrocyclones, and piping fromthe mills are rubber lined. Some hydrocyclones are being lined with noncombustible ceramics.

Fig. 77. Concentrator complex at diamond mine. (Photo courtesy of Rio Tinto)



Hydrometallurgy: selective dissolution of metals from ores and concentrates using solvents or solutions.Examples are in-situ, heap or vat leaching and solvent, liquid-liquid, or liquid-ion exchange extraction.Ammonia, kerosene, sodium cyanide, mineral acids (i.e., sulfuric acid), and water are used in hydrometal-lurigical processes. Processes may be at elevated temperatures and pressures. Two examples ofhydrometallurgical processes are shown in Figures 99 and 100.

Jig: milling equipment used to concentrate ore on a screen submerged in water, usually by a reciprocatingmotion of the screen, or by the action of the flowing water. Jigs can be constructed of high density plastics andcan ignite from hot work when dry.

Launder: chute or trough for conveying pulp, water, or powdered ore in a mill. Launders can be rubber lined.

Leachate (Lixivium): mineral-in-solution product of leaching. Also called pregnant liquor.

Leaching (lixivation): separation, selective removal, or dissolving-out of soluble constituents from an ore bythe natural action of percolation water or reagent solutions. Commonly used to recover fine grain gold, silverand zinc from low-grade ores using sodium or calcium cyanide or sulfuric acid solutions. (See cyanidation,heap, and vat leaching)

Leach Pad (Leach Dump): impervious layer, usually of compacted clay over which rests a plastic liner, onwhich a low grade ore pile is placed for solvent leaching. (See heap leaching)

Liquid-Ion Exchange: hydrometallurgical method using liquid solvents such as kerosene, ammonia, acids,and cyanides in an electrolytic bath to dissolve, depose and recover metals. A form of solvent extraction.

Liquid-Liquid Extraction: see solvent extraction.

Liner: hard metallic alloy, ceramic, or polymeric based material used to line the interior of mills, pipes,cyclones, pumps, pump impellers, spiral separators, troughs, flotation cells, and slurry tanks. Liners provideabrasion resistance to interior steel surfaces. Rubber linings are prevalent, creating significant fire potentials

Fig. 78. Gold mine concentrating facility. Due to tropical location much of process area is located outdoors. This facilityhas a single ball mill with two SAG mills, one on either side. Tanks at rear of photo are part of a vat leachingoperation.



Fig. 79. In-pit crushing station at large copper mine.(Courtesy of Rio Tinto, Kennecott Copper, Bingham Canyon Mine, Utah)

Fig. 80. Drawing of a movable crusher mounted on a crawler transporter.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



in otherwise noncombustible occupancies. A liner is also a mining term denoting a brick, concrete, wood,or other casing in a mine tunnel or shaft.

Magnetic Separation: concentration using magnetic fields to differentially separate ferrous materials from non-ferrous materials. Iron ore compounds are commonly recovered by this method. Examples of electromagneticseparators are drum magnet and wet high intensity magnetic separators (WHIMS).

Pebble Mill: rotating grinding cylinder using ceramic or physically formed natural rock pebbles as the grindingmedia. A form of ore comminution.

Polishing Pond: final pond in a series of tailings or settling ponds through which mill waste effluents passbefore they are discharged into the natural environment.

Polymeric Materials: hydrocarbon based substances that are used in construction or found in mining andore processing occupancies. Examples are coal deposits, wood timber sets, plastic insulation on electriccables, synthetic rubbers used in equipment liners, conveyor belts, etc.

Pyrometallurgy: concentrating processes using refractory-lined furnaces and high temperatures created byelectrical energy, by burning fossil fuels, or by burning ore at extremely high temperatures. Refined metals areproduced. Drying, roasting, sintering, distilling, smelting, and fire refining are all examples of pyrometallurgicalprocesses.

Pulp: mixture of water and ground or pulverized ore or coal capable of flowing or being pumped as a liquidor slurry.

Reagent: liquid used in beneficiation flotation or solvent exchange process to cause bubble formation orfor selective absorption or adsorption of the desired mineral or coal. Flotation reagents fall into four generalcategories: collector agents (i.e., xanthates, fatty acids and petroleum sulfonates); pH modifiers (i.e., lime,

Fig. 81. Photo of a mobile crusher at open pit mining operation. (Courtesy of Alcoa)



Fig. 82. Drawing of a gyratory crusher inside a multistory reinforced concrete crushing facility. In this facility, rail mountedcars from an underground mine are brought to the top of the building and the ore load is delivered into the crusherthroat by a tipple. Note the spare crusher cone stored next to the tipple. Crushed ore is sent via conveyor beltto an ore pile or surge bin from which it is further crushed or processed. (Figure courtesy of Society of Mining,Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)



Fig. 83. Drawing of in-situ solution mining (cyanide leaching) in an open pit. At top is a drawing of a typical heap leachpad using cyanide leaching. (Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME),Littleton, Colorado)

Fig. 84. Photo of a copper electro-refining cell (tank) house. Walkways between cells are wood plank. Cells areconcrete lined with a thin polymer plastic. (Courtesy of Cominco Quebrada, Chile)



soda ash, sodium hydroxide, and sulfuric acid); activator agents (i.e., copper sulfate, calcium chloride andlead acetate); and frother agents (i.e., methyl isobutyl carbinol [MIBC], pine oil, kerosene, variousdepressants, and sodium cyanide). MIBC is a common frother used in both mineral and coal beneficiationand is a low flash point flammable liquid. See Table 2 for a list of common flotation reagents and their firehazard characteristics.

Rod Mill: rotating grinding cylinder using long steel rods as the grinding media. A form of ore comminution.

Semi-autogenous (SAG) mill: rotating grinding cylinder using a combination of steel balls and ore-to-ore con-tact as the grinding media. A form of ore comminution. World-class size SAG mills are 36 ft (11 m) in diam-eter and 18 ft (5.4 m) long, driven by 16,000 HP (11936 KW) synchronous motors. (See Grinding for photoof a SAG mill)

Screen: flat or cylindrical device surfaced with openings to selectively size rocks or ore. Screens can shakeor rotate and be constructed of metal or high density plastic. Commonly found downstream of crushers ormills in a grind circuit.

Sheave Wheel: large grooved wheel at the top of a headframe over which the wire hoisting rope passes.(See Fig 5 for photo of sheave wheel on head frame)

Size Reduction (Comminution): breaking, crushing, and grinding wet or dry ore to achieve desired size forconcentration. Grizzlies, cone and jaw crushers, autogenous and semi autogenous (SAG) mills, ball and rodmills, tumblers, and screening machinery are all examples of size reduction equipment.

Solvent (Liquid-Liquid) Extraction (SX): separation of one or more substances from a mineral mixture by treat-ing a solution of the mixture in a solvent. The solvent is usually comprised of a carrier, an extractant, anda phase modifier that will dissolve the desired mineral, leaving the undesirable materials for disposal or otherprocessing. Kerosene is commonly used as the carrier, which normally accounts for 80–85% of the total sol-vent volume. Common extractants, which account for 10–20% of the solvent, are tri-butyl phosphate andquartenary amines. A typical phase modifier is isodecanol, which may account for 5% of the total volume of

Fig. 85. Photo of plastic screen (blue) inside flotation tank. Also refer to photo of flotation circuit under Beneficiation, above.



the solvent. Tanks in newer SX processes are commonly FRP or other plastic. Older processes may featurewood tanks. SX is commonly used for copper, nickel and uranium ores. (See Fig 100 for a typical SX processflow diagram.)

Tailings (Tails): gangue and other refuse material resulting from the washing, concentrating, and treatmentof ground ore, which is generally too poor in mineral value to be treated further.

Tailings Pond(Stack/Pile/Dam): liquid or semi-liquid waste gangue and by-product trace reagent and otherchemicals derived from processing and concentration of ore. The waste product is delivered by pipeline to thepond in a water slurry. The pond is usually held in place by a sloped earthen dam. Most of the water is drainedor decanted and returned to the process. Remaining water is allowed to evaporate over time, stabilizing thestack and leaving the undesired heavy metals or toxins (such as trace cyanides) to settle and be retained. Tail-ings ponds can be hundreds of feet (meters) high with steep walls and thousands or feet (meters) long andwide, if not miles (kilometers). Dam wall stability is of concern to prevent failure and downstream flood-ing. Liquefaction (and resultant failure) of a poorly designed earthen dam can be caused by earthquakes,sonic vibrations, floods, heavy surface water runoff, or other unusual natural occurrences. Modern tailingsponds have durable plastic liners and their dams are specially engineered structures featuring layers of rockand compacted earth, designed by experts to resist worst case prevailing natural events. The most com-mon root cause failures of tailings piles are improper filling, day-to-day operation, and maintenance.

Thickener (Thickener-Settler): open tank with a sub-surface rake for solid-liquid separation of desired mineral.The liquid is usually an aqueous solution and overflows the top into troughs. New troughs and thickner tanksare concrete or steel and can be rubber lined. Older plants may use wood tanks and troughs.

Trommel: large, rotating size separation screen at the outlet of a grinding mill, such as a SAG mill. The screenis normally covered by a metal shroud. Trommel screens are often constructed of high density polyurethaneplastic. They are usually ignited by hot work operations when the enclosing shroud is open for maintenance.

Fig. 86. Photo of world-class size semi-autogenous (SAG) mill in copper concentrator facility. (Courtesy of Rio Tinto)



APPENDIX B DOCUMENT REVISION HISTORY

September 2010. Minor editorial changes were made for this revision.

May 2010. Minor editorial changes were made for this revision.

May 2007. Section 2.4.8 on solvent extraction plants was completely revised.

September 2004. References to FM Global earthquake zones have been modified for consistency with DataSheet 1-2, Earthquakes.

January 2001. This version of the document has been reorganized to provide a consistent format.

Fig. 87. Photo of large DC drive motor for this SAG mill. (Courtesy of Rio Tinto)



Fig. 88. Photo of parallel ball mills in a copper concentrator facility. Often two small ball mills are paired withone large SAG mill for final grinding. (Courtesy of Rio Tinto)

Fig. 89. Cutaway view drawing of a rod mill, showing internal components. Note the layered rods which are steel barswhich vary in diameter and length, depending on the size of the mill. The rods rotate with the mill, fine grinding the ore.



Fig. 90. Process flow diagram of a grind circuit featuring multiple stages of crushing with ball and rod mill grinding.

Fig. 91. Process flow diagram of a grind circuit featuring a single crusher with SAG and ball mill grinding.



Fig. 92. Photo of a cross valley gold heap leaching operation, built into a sloping mountain. Note the bench pyramid shapeand exposed rubber liner (black area at upper right). Pregnant solution pond is at lower center. Note size of orehaulage truck at center in relationship to size of heap leach pile. (Photo courtesy of Newmont Mining Company,Yanacocha Mine, Peru)

Fig. 93. Drawing of heap leach operation showing pile and pregnant solution collection pond.



Fig. 94. Closeup drawing of heap leach pile showing cyanide solution distribution system.

Fig. 95. Photo of rubber lined raffinate pond at copper heap leaching and solvent extraction mine.(Courtesy of Cominco Quebrada, Chile)



Fig. 96. Photo of hydrocyclone bank (six hydrocyclones) positioned over a collection tank.These hydrocyclones and the discharge tank are all rubber lined.

Fig. 97. Close up view of single rubber lined hydrocyclone in bank.



Fig. 98. Sketch of water injected hydrocyclone.(Figure courtesy of Society of Mining, Metallurgy, and Exploration, Inc. (SME), Littleton, Colorado)

Fig. 99. Process flow of a typical heap leaching, carbon-in-pulp, and electrowinning circuit forhydrometallurgical recovery of gold and silver.



Fig. 100. Typical solvent extraction process flow for copper.

Fig. 101. Photo of rubber liner inside a ball mill.



Fig. 102. Photo of rubber liner inside a large diameter steel pipe flange.



Fig. 103. Photo of pyrometallurgical process zinc roaster.(Photo courtesy of Cominco, Peru)



Fig. 104. Shaker screen, constructed of high density polyurethane plastic.

Fig. 105. Photo of SX plant at copper mine. (Photo courtesy of Cominco Quebrada, Chile)



Fig. 106. Tailings pond at zinc refinery.

Fig. 107. Thickener tanks at copper concentrator plant. (Courtesy of Rio Tinto)



Fig. 108. Photo of exposed plastic trommel screen at outlfow of large SAG mill.



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