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NATURAL FORMATION OF MINERAL RESOURCES Mineral Resource – is a concentration of naturally occurring material in or on the earth’s crust that is extracted & used at a reasonable cost to consumers. Common minerals: calcite, quartz, mica Mineral Resources 1) Metallic – iron, copper, aluminum 2) Non-metallic – salt, sand 3) Energy – coal, oil, natural gas, uranium ORES (ROCKS) Commercially valuable minerals and rocks are referred to as industrial minerals. Rocks from which minerals are mined for economic purposes are referred to as ores. Minerals form over geologic time (millions of years) and are therefore classified as nonrenewable resources. HOW DO WE FIND MINERAL DEPOS ITS? 1) Drilling deep wells and extracting core samples 2) Aerial photos & satellite images to reveal protruding rock formations (outcrops) 3) Radiation measure – detect uranium ore Hydrothermal Vents Create ORES USGS defines mineral resources into two categories 1) identified & 2) undiscovered Reserves are identified as resources from which a usable nonrenewable mineral can be extracted for profit. ORES from WEATHERING Sedimentary Sorting (gold) Evaporite Deposits (salt) Residual Deposits (bauxite) Overburden – layers of soil & rock overlying a mineral deposit & is removed during surface mining. WORDS TO SPOILS KNOW Subsidence – slow or rapid sinking of part of the ground that is not slope related. Smelting – process in which a desired metal is separated from the other elements in an ore. Waste material Gangue Tailings Piles of Gangue STRIP MINING & MOUNTAIN TOP REMOVAL Exposure of toxic materials that will leach into ground and surface waters Wildlife is exposed to toxins Sediment runoff COMBUSTION (electrical production) STRIP MINING Land Erosion (sediment runoff) Emits - SO2, NOx, CO2 Acid Mine Drainage Inorganic Mercury in Atmosphere - Habitat Loss Subsurface MINING Land Collapse Fires - fumes Black Lung Disease Acid Mine Drainage methylmecury in aquatics Ground-level ozone – smog Respiratory Disease • Open Pit Mines (coal, copper, uranium, lead, gold, silver) • Exposes waste rock like pyrite (FeS2) which can react with water to form sulfuric acid. • Releases ferric ions (Fe++) • Leaches toxic heavy metals (Al3+, Zn2+) • Red Staining - “Yellow Boy” • Changes pH (can be higher or lower as it degrades natural buffers) • Increases conductivity and hardness TYPICAL COAL BURNING POWER PLANTS ENVIRONMENTAL IMPACTS High CO2 emissions (greenhouse gas) Other emission: SO2 (acid rain); NOx; & Mercury Human health impact – respiratory diseases China largest global consumer of coal reserves Large disruption to land Acid Rain Global Climate Change Coal Supplies 50% of our electrical needs in the United States COAL GASIFICATION Produces synthetic natural gas by coal liquefaction Advantages Large supply Vehicle Fuel Disadvantages High land impact Increased Surface Mining High CO2 emissions Higher cost Lower net yield CLEANING UP COAL! Cleaning - Chemical/Physical cleaning of coal prior to combustion Fluidized-Bed Coal Combustion 1) Removes most of the sulfur dioxide 2) Reduces emissions of NOx 3) Burns coal more efficiently and cheaply than conventional methods Scrubbing - injection of limestone into gases, reaction of carbonate with sulfur dioxide produces calcium sulfate (sludge) . ENVIRONMENTAL IMPACT TO MINING PRACTICES & USE Mining Exploration; Extraction Processing Transportation; purification, manufacturing Use transportation or transmission to individual user, eventual use, and discarding Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; scarring; heat; subsidence Solid waste; radioactive waste; air, water, & soil pollution; noise; safety & health hazards; heat Noise; ugliness thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat ENVIRONMENTAL DAMAGE FROM MINING PRACTICES Subsurface Mine Opening Surface Mine Runoff of sediment Acid drainage from reaction of mineral or ore with water Spoil banks Leaching of toxic metals and other compounds from mine spoil Percolation to groundwater Fig. 14.7, p. 326 Leaching may carry acids into soil and ground water supplies The ruins of Centralia Pennsylvania no longer exists on some maps. The story began sometime in 1961 along the outskirts of town when trash was burned in an old open pit mine. The fire in the open pit caught an exposed vein of coal on fire. The coal then began to burn underground. That was in 1961. Over 40 years and 40 million dollars later the fire still burns through old coal mines and veins following the coal under the town and the surrounding hillsides. The fire, smoke, fumes and toxic gases that came up though the back yards, basements and streets of Centralia practically ripped the town apart. Attempts to put the fires out were unsuccessful. IMPACT: 1962: Pop. Of 1,100 – 2,000 545 Families & Businesses 1996: Pop. Of 46 20 Families - NO businesses