University of SaskatchewanUniversity of Saskatchewan

Geological EngineeringGeological EngineeringGEOE 498.3GEOE 498.3

Introduction to Mineral EngineeringIntroduction to Mineral Engineering

Lecture # 3Lecture # 3

Production RateProduction RateProductivityProductivityStope ProductionStope ProductionMine ProductionMine Production

U/G InfrastructureU/G Infrastructure

Productivity vs. ProductionProductivity vs. Production Productivity is the rate at which a task is Productivity is the rate at which a task is

completed or ore is produced. In mining it is completed or ore is produced. In mining it is usually reported in units per machine or man usually reported in units per machine or man hour.hour.Drilling: metres per drill - HourDrilling: metres per drill - HourMucking: Tonnes per LHD - HourMucking: Tonnes per LHD - HourDevelopment: metres per man-shift.Development: metres per man-shift.

Production is the total amount produced. In Production is the total amount produced. In mining it is usually the total production per day, mining it is usually the total production per day, week, month or year.week, month or year.

Determining Productivity and ProductionDetermining Productivity and Production

Rule’s of ThumbRule’s of Thumb

Benchmarking Benchmarking

Historical DataHistorical Data

Equipment SpecificationsEquipment Specifications

First Principle CalculationsFirst Principle Calculations

Rule of Thumb

Rule of Thumb – An easy to remember guide that falls somewhere between an engineered solution and an experienced or educated guess.

Are the Rules always correct? Absolutely no. Can they provide a quick answer or a starting place? Absolutely yes.

The primary usage of Rules of Thumb should be in the development of conceptual designs and feasibility studies or, when a quick decision is required in the solution of an operating problem.

When the time arrives for final design and actual construction, Rules of Thumb are no substitute for sound engineering practices.

Productivity - Rule’s of ThumbProductivity - Rule’s of ThumbActivity Measurement ProductivitySink timber shaft m/day 2 - 2.8Sink bald concrete shaft m/day 3 - 4Sink equipped concrete shaft m/day 2.4 - 3.6Equip concrete shaft m/day 10 - 15Cut shaft stations - slusher cu m/day 50 - 65Cut shaft stations – LHD 65 - 95Drive raw raises up to 10 m m/m-sh 0.5 - 0.7Drive timbered raises m/m-sh 0.45 - 0.6Drive alimak raises m/m-sh 0.75 - 1.0Raise bore drill

Set up days 2 - 5Drill Pilot m/day 20 - 25Ream m/day 7 - 10

Track drift m/m-sh 0.5 - 0.75Trackless Drift m/m-sh 0.65 - 1.0Ramp m/m-sh 0.55 - 0.8Drill and Install Rock Bolts (stoper) m/m-sh 45 - 60Drill and Install Rock Bolts (mobile) m/m-sh 100 - 125Drill Jack Leg m/m-sh 10 - 15Drill Stoper m/m-sh 8 - 12Drill Jumbo m/m-sh 75 - 100Drill Tophammer (small diameter < 76mm) m/machine-shift 75 - 120Drill Tophammer (large diameter > 105mm) m/machine-shift 25 - 50Drill ITH m/machine-shift 25 - 50

Mucking Mucking ProductivityProductivity

Productivity - DrillingProductivity - Drilling

Productivity - DrillingProductivity - Drilling

Mucking Productivity - TruckingMucking Productivity - Trucking

Mucking Productivity Large ScoopMucking Productivity Large Scoop

BenchmarkingBenchmarking

Gathering information and statistically analyzing Gathering information and statistically analyzing how other similar operation are performing.how other similar operation are performing.ProductionProductionProductivityProductivityCostCostSafetySafety

Information is not always readily available.Information is not always readily available.

Must ensure that orebody, skill of labour, work Must ensure that orebody, skill of labour, work organization, consumable costs, etc. are in fact organization, consumable costs, etc. are in fact similar.similar.

BenchmarkingBenchmarking

First Principle CalculationsFirst Principle Calculations

Zero based calculations where the Zero based calculations where the production or productivity estimate is production or productivity estimate is created by the mine engineer.created by the mine engineer.

Typically used at the detailed design Typically used at the detailed design stage.stage.

Equipment specifications, quotations, Equipment specifications, quotations, detailed drawings, established detailed drawings, established engineering practices form the bases.engineering practices form the bases.

Equipment ManufacturerEquipment Manufacturer

Equipment Manufacturers have detailed Equipment Manufacturers have detailed specifications for their equipment that specifications for their equipment that will provide data on:will provide data on:ProductivityProductivityEnergy consumptionEnergy consumptionWater ConsumptionWater ConsumptionCompressed AirCompressed AirSize of OpeningsSize of OpeningsWeightsWeights

Equipment ManufacturerEquipment Manufacturer

The specifications are typically derived under The specifications are typically derived under ideal conditions.ideal conditions.

The mine engineer must factor in site specific The mine engineer must factor in site specific conditions such as:conditions such as:Skill of work forceSkill of work forceEnvironment (heat, depth, humidity)Environment (heat, depth, humidity)Condition of openingsCondition of openingsHardness of rockHardness of rockMaintenanceMaintenanceAvailability and UtilizationAvailability and Utilization

Play LHD VideoPlay LHD Video

First Principle First Principle Shotcrete Shotcrete

CalculationCalculation

Input Data

Arch back is assumed. 20%Roughage Factor 20%Rebound Factor 20%Overlap Factor 0.5 mDrift width 4.5 mDrift height 4.5 mRound length 3.2 mShotcrete thickness 3.0 inShotcrete Height from Floor 1.5 m

Calculated DataShoulder Height 3.60 mBack Arc Length ... 4.97 mPerimeter Coverage of Shotcrete 9.2 mShotcrete thickness 0.0762 m

Results

Theoretical volume 2.58 m^3Actual volume considering overlap, surface roughness and rebound 3.72 m^3

Productivity Mucking EquipmentProductivity Mucking Equipment

Mucking Productivity - TruckingMucking Productivity - Trucking

Productivity Drill EquipmentProductivity Drill Equipment

Tunneling EquipmentTunneling Equipment

Historical DataHistorical Data

Usually applies to existing operations and Usually applies to existing operations and is used to forecast production and create is used to forecast production and create annual operating budgets.annual operating budgets.If a site does things the way they If a site does things the way they

always did, can expect the same always did, can expect the same results.results.

Data gathered from time studies.Data gathered from time studies.

May also be used when estimating May also be used when estimating productivity, production and costs for an productivity, production and costs for an expansion.expansion.

SummarySummary In most estimating situations a combination of In most estimating situations a combination of

history, benchmarking, rule of thumb and first history, benchmarking, rule of thumb and first principle calculations are used.principle calculations are used.

CAUTION: in mining CAUTION: in mining “stuff happens”“stuff happens” It is important It is important to build efficiency factors and reality into the estimate.to build efficiency factors and reality into the estimate.Types of Delays:Types of Delays:

• Gas Check• Equipment down• Ground Conditions• No Materials• Surveying• Air, water, vent, power• Travel and Breaks

Equipment AvailabilityEquipment AvailabilityAvailability (Operational Availability) It is the probability that an item will operate satisfactorily at a given point in time when used in

an actual or realistic operating environment. Includes all sources of downtime, (administrative, logistic as well as actual time to repair) Operational availability is used to isolate the effectiveness and efficiency of maintenance

operations. Operational availability can be calculated on a calendar basis or on a scheduled work basis. Uptime Equipment is available to the operators Total Time Based on 24-7, i.e. 168 hours in a week Scheduled Time Based on work schedule, i.e. 2x10hr shifts per day 7 days per week = 140

hours /week

AOT = Total Operational Availability = uptime/total time AOE = Effective Operational Availability = uptime/scheduled time Rule of Thumb - New and/or well maintained equipment will have 80-

90% effective availability

Equipment UtilizationEquipment Utilization

Utilization Utilization is defined as the percentage of time in which equipment is in production. In other

words production is not prevented by equipment malfunction, operating delays, or scheduled downtimes.

Utilization is used to isolate the effectiveness and efficiency of mine operations.

UT = Total Utilization = equipment operating time/total time US = Effective Utilization = equipment operating time/scheduled time UA = Actual Utilization = equipment operating time/uptime

Rule of Thumb - New and/or well maintained equipment should have 60-70% effective utilization

Equipment ReliabilityEquipment Reliability

ReliabilityReliability: is the probability that a piece of equipment or : is the probability that a piece of equipment or system will perform its required function under stated system will perform its required function under stated conditions for a stated period of time.conditions for a stated period of time.

MTBF: Mean Time Between Failures – how long a piece of MTBF: Mean Time Between Failures – how long a piece of equipment or system will operate before it fails.equipment or system will operate before it fails.

TTR : Time to repairTTR : Time to repair

Preventative Maintenance : routinely schedule equipment Preventative Maintenance : routinely schedule equipment for service and inspection of key componentsfor service and inspection of key components

Predictive Maintenance : Schedule changeout of key Predictive Maintenance : Schedule changeout of key components and major overhauls or rebuilds prior to components and major overhauls or rebuilds prior to equipment failure.equipment failure.

Example 1Example 1

Estimate development advance and metres per Estimate development advance and metres per manshift in a typical developmentmanshift in a typical development

Assumptions:Assumptions:RMR : Very StrongRMR : Very Strong2 man Crew,2 man Crew,2 boom Jumbo, stoper for ground support, 2 boom Jumbo, stoper for ground support,

med sized scoopmed sized scoopRound size is 5x5x3.5Round size is 5x5x3.5Drill pattern requires 65 holesDrill pattern requires 65 holesBolting pattern is 1.5x1.5 and 2m long boltsBolting pattern is 1.5x1.5 and 2m long bolts

Example 1Example 1

Estimating Mine ProductionEstimating Mine Production

Taylor’s Rule is a means of estimating Mine Life Taylor’s Rule is a means of estimating Mine Life and Daily Production. It has been calibrated and Daily Production. It has been calibrated against many mines over several years and is against many mines over several years and is adequate for pre-feasibility level estimates.adequate for pre-feasibility level estimates.

L=0.2TL=0.2T0.250.25

PR=T/(LxDPY) PR=T/(LxDPY) Where

L=Mine LifeT=Resource (inc. Dilution and Recovery)

PR=Daily ProductionDPY=Scheduled Days Per Year

Example 2Example 2

Orebody A is 2 000 000 tOrebody A is 2 000 000 t The expected Recovery is 90% and dilution is The expected Recovery is 90% and dilution is

estimated at 20%, therefore the Resource = 2mt estimated at 20%, therefore the Resource = 2mt x .9 x 1.2 = 2.16 mtx .9 x 1.2 = 2.16 mt

L=0.2TL=0.2T0.250.25

L = 0.2 x (2 160 000)L = 0.2 x (2 160 000)0.250.25

L = 7.7 yearsL = 7.7 years If the mine is scheduled to operate 350 days per If the mine is scheduled to operate 350 days per

year, then the daily production is year, then the daily production is PR=T/(LxDPY)PR=T/(LxDPY)PR=2 160 000/(7.7 x 350)PR=2 160 000/(7.7 x 350)PR ~ 800 tpdPR ~ 800 tpd

Example 3Example 3

Orebody B is 20 000 000 tOrebody B is 20 000 000 t The expected Recovery is 80% and dilution is The expected Recovery is 80% and dilution is

estimated at 10%, therefore the Resource = 20mt estimated at 10%, therefore the Resource = 20mt x 0.8 x 1.1 = 17.6 mtx 0.8 x 1.1 = 17.6 mt

L=0.2TL=0.2T0.250.25

L = 0.2 x (17 600 000)L = 0.2 x (17 600 000)0.250.25

L = 12.95 yearsL = 12.95 years If the mine is scheduled to operate 350 days per If the mine is scheduled to operate 350 days per

year, then the daily production is year, then the daily production is PR=T/(LxDPY)PR=T/(LxDPY)PR=17 600 000/(12.95 x 350)PR=17 600 000/(12.95 x 350)PR ~ 3900 tpdPR ~ 3900 tpd

Example 4Example 4

Orebody A is a nearly vertical quartz vein Orebody A is a nearly vertical quartz vein containing 0.25 oz gold per tonne (insitu). It is a containing 0.25 oz gold per tonne (insitu). It is a tabular, deposit that measures 215 metres on tabular, deposit that measures 215 metres on strike, 240 m high and 15m thick. It has a strong strike, 240 m high and 15m thick. It has a strong ore and f/w and a week h/w. The top of the ore and f/w and a week h/w. The top of the orebody is 200 metres below surface and the orebody is 200 metres below surface and the bottom is 440 metres below surface. Both ore bottom is 440 metres below surface. Both ore and waste have a SG of 2.6 t/mand waste have a SG of 2.6 t/m33

The chosen mining method is Transverse The chosen mining method is Transverse Mechanized Cut and Fill.Mechanized Cut and Fill.

Stope dimensions Have been established as 7m Stope dimensions Have been established as 7m wide x 24m high x 15 m longwide x 24m high x 15 m long

Example 4Example 4

Determine:Determine:Average tonnes per day per stope of Average tonnes per day per stope of

ore and waste.ore and waste.Number of stopes required to meet Number of stopes required to meet

daily production target.daily production target.The truck fleet size.The truck fleet size.

Example 5Example 5

Orebody B is a thick, tabular steeply dipping Orebody B is a thick, tabular steeply dipping Nickel deposit with a diluted grade of 3% Ni. It Nickel deposit with a diluted grade of 3% Ni. It averages 330 metres on strike, 400 m high and averages 330 metres on strike, 400 m high and 40m thick. It has a strong ore and h/w and a 40m thick. It has a strong ore and h/w and a moderate f/w. The top of the orebody is 100 moderate f/w. The top of the orebody is 100 metres below surface and the bottom is 500 metres below surface and the bottom is 500 metres below surface. The recovered ore has an metres below surface. The recovered ore has an S.G. of 3.8 and the waste has an SG of 2.6 t/mS.G. of 3.8 and the waste has an SG of 2.6 t/m33

The chosen mining method blasthole stoping The chosen mining method blasthole stoping with paste fillwith paste fill

Stope dimensions Have been established as 15m Stope dimensions Have been established as 15m wide x 32.5m high x 20m longwide x 32.5m high x 20m long

Example 5Example 5

Determine:Determine:Average tonnes per day per stope of Average tonnes per day per stope of

oreoreNumber of stopes required to meet Number of stopes required to meet

daily production target.daily production target.If 30 metres of development is If 30 metres of development is

required to access each stope, required to access each stope, calculate tonnes of waste per daycalculate tonnes of waste per day

SequencingSequencing

Once the number of stopes are Once the number of stopes are determined, they need to be sequenceddetermined, they need to be sequenced

Considerations:Considerations:StressStressVoidsVoidsFill Cure TimeFill Cure TimeLogistics (congestion on a level)Logistics (congestion on a level)VentilationVentilationCapital or access developementCapital or access developement

Chevron & Primary/Secondary Mining Chevron & Primary/Secondary Mining

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