What is it? Why do we do it? What does it do to the Earth? How can we be more sustainable? Mining.

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    31-Mar-2015

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<ul><li>Slide 1</li></ul> <p>What is it? Why do we do it? What does it do to the Earth? How can we be more sustainable? Mining Slide 2 Naturally occurring in earths crust Must be extracted, processed Examples Energy (oil, coal, natural gas, uranium) Metallic minerals (aluminum, iron, copper, gold) Nonmetallic minerals - Aggregate: sand, gravel Fertilizers: potash, phosphorous Evaporites: gypsum, halite (salt) Building Materials: limestone, marble Nonrenewable! Slide 3 A rock that contains a mineral. Must contain profitable amount High grade = large amount of desired mineral Low grade = smaller amount of desired mineral Slide 4 1. Magma (Igneous): Cooling process causes mineral containing rocks to form Gold, silver, lead, mercury, copper (found in veins of quartz) Hydrothermal Copper, lead, zinc, silver, gold, sulfur Manganese nodules (sea floor deposits) Steel processing 2. Sedimentary Processes Placer Deposits (river gravels) gold Evaporites Halite, gypsum, borax (soap) 3. Weathering 1. Bauxite (aluminum), Fe oxides (pigments) Slide 5 Slide 6 Identified Known location, quantity and quality based on direct evidence Reserves Identified resources that can be extracted profitably Undiscovered Potential supplies that are assumed to exist Slide 7 Slide 8 Slide 9 Gold Electronics, jewelry Aluminum Packaging, cars, airplanes Steel (alloy containing iron) Buildings, vehicles Sand Glass, bricks, concrete Limestone Cement, concrete, road rock, building materials Slide 10 Slide 11 Key terms: 1.Overburden: the soil &amp; rock that lies above the economically important rock. 2.Gangue: worthless minerals/material that surrounds ore 3.Smelting: using heat &amp; chemicals to turn ore into useable mineral 4.Tailings: piles of waste left behind after extraction, contains gangue Slide 12 Advantages Income! Revenues for cities, states and countries Employment Progress buildings, cars, electronics Uses lots of energy Disturbs land Erodes soil Produces a lot of waste Pollutes air, water, soil Disadvantages Slide 13 Surface mining Removal of shallow deposits Overburden removed Rock/soil on top of deposit Discarded as spoils Used in 90% of non-fuel mineral/rock resources Used in 60% of coal mined in U.S. Removal of deep deposits Often used for coal and metal ores Deep vertical shaft is dug Tunnels must be blasted Machinery used to reach deposits Subsurface mining Slide 14 Surface Drift Slope Shaft Hard Rock Borehole Fracking Subsurface Open Pit Strip Mountaintop Removal Placer Hydraulic Dredging Slide 15 Slide 16 Slide 17 Open-pit mining Holes are dug Ores are removed Iron, copper, gold, sand, gravel, stone Used for horizontal beds of minerals Area strip mining: flat land Contour strip mining: hills Coal (70%) Strip mining Slide 18 Used on hilly or mountainous terrain. Unless the land is restored, a wall of dirt is left in front of a highly erodible bank called a highwall. Figure 15-13 Slide 19 Mountain top removed Exposes deposits Prominent in Appalachian mountains Ex. Coal Slide 20 Gold Mining Placer Deposits (gravity separation) Panning Sluicing Dredging Hard Rock Deposits Open pit Hydraulic mining (sometimes with Hg) Subsurface - S. Africa 12, 800 feet underground Cyanide is used to extract gold Slide 21 1. Scarring/disruption of land Overburden/Spoils left behind, vegetation cant grow well H2SO4 acid runoff Sediment, erosion, loss of topsoil Subsidence, cave-ins (sink holes), explosions Slide 22 2. Processing involves many chemicals (sulfuric acid, mercury, cyanide) Creates toxic waste during processing Tailings: Often stored in valleys As, Hg, CN, H2SO4 Can collapse and get into ecosystem Streams/Groundwater polluted with waste material Tailings: H2SO4, Hg, CN (Cyanide) Overburden: Sediment Overburden: H2SO4 leaches heavy metals such as As, Cd, Pb, Zn Air pollution from processing Highest industrial air polluter of toxic emissions! Slide 23 Slide 24 3. Forests removed Loss of Biodiversity Increased Erosion 4. Disease (subsurface) COPD chronic bronchitis, emphysema Black lung disease Slide 25 Slide 26 Clean up and restore mining sites 500,000 surface sites in U.S. $70 billion to clean up Subsurface disturbsSlide 27 Designed to encourage mineral exploration on U.S. public lands and populate the West Individuals could claim land Must spend $500 to improve land Could pay $6-12 for land owned by all U.S. citizens Could build, sell, lease, use it for whatever Frozen in 1995 Some land still being transferred at 1872 prices! 1992 modification: must post bonds to cover clean up cost in case of bankruptcy Mining companies trying to weaken Slide 28 surface coal mining Established a program for regulating surface coal mining and reclamation activities Established mandatory uniform standards for these activities on state and federal lands requirement that adverse impacts on fish, wildlife and related environmental values be minimized reclamation of land after mining was completed Created an Abandoned Mine Reclamation Fund for use in reclaiming and restoring land and water resources adversely affected by coal mining practices. </p>

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