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Geology and Nonrenewable Minerals Chapter 14 Core Case Study: Environmental Effects of Gold Mining Gold producers • • • • South Africa Australia United States Canada Cyanide heap leaching • Extremely toxic to birds and mammals • 2000: Collapse of a dam retaining a cyanide leach pond • Impact on organisms and the environment Gold Mine with Cyanide Leach Piles and Ponds in South Dakota, U.S 14-1 What Are the Earth’s Major Geological Processes and Hazards? Concept 14-1A Gigantic plates in the earth’s crust move very slowly atop the planet’s mantle, and wind and water move the matter from place to place across the earth’s surface Concept 14-1B Natural geological hazards such as earthquakes, tsunamis, volcanoes, and landslides can cause considerable damage The Earth Is a Dynamic Planet What is geology? Three major concentric zones of the earth • Core • Mantle • Including the asthenosphere • Crust • Continental crust • Oceanic crust: 71% of crust Major Features of the Earth’s Crust and Upper Mantle Volcanoes Abyssal hills Abyssal Oceanic ridge floor Ab ys sa lp lai n Oceanic crust (lithosphere) Abyssal floor Trench Mantle (lithosphere) Folded mountain belt Craton Abyssal plain Continental shelf Continental slope Continental rise Continental crust (lithosphere) Mantle (lithosphere) Mantle (asthenosphere) Fig 14-2, p 346 The Earth Beneath Your Feet Is Moving (1) Convection cells, or currents Tectonic Plates Lithosphere The Earth Beneath Your Feet Is Moving (2) Three types of boundaries between plates • Divergent plates • Magma • Oceanic ridge • Convergent plates • Subduction • Subduction zone • Trench • Transform fault; e.g., San Andreas fault The Earth’s Crust Is Made Up of a Mosaic of Huge Rigid Plates: Tectonic Plates A Mine, use, throw away; no new discoveries; rising prices Recycle; increase reserves by improved mining technology, higher prices, and new discoveries Production B Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries C Present Depletion time A Depletion Depletion time B time C Time Stepped Art Fig 14-23, p 361 Market Prices Affect Supplies of Nonrenewable Minerals Subsidies and tax breaks to mining companies keep mineral prices artificially low Does this promote economic growth and national security? Scarce investment capital hinders the development of new supplies of mineral resources Case Study: The U.S General Mining Law of 1872 Encouraged mineral exploration and mining of hardrock minerals on U.S public lands Developed to encourage settling the West (1800s) Until 1995, land could be bought for 1872 prices Companies must pay for clean-up now Is Mining Lower-Grade Ores the Answer? Factors that limit the mining of lower-grade ores • Increased cost of mining and processing larger volumes of ore • Availability of freshwater • Environmental impact Improve mining technology • Use microorganisms, in situ • Slow process • What about genetic engineering of the microbes? Can We Extend Supplies by Getting More Minerals from the Ocean? (1) Mineral resources dissolved in the ocean-low concentrations Deposits of minerals in sediments along the shallow continental shelf and near shorelines Can We Extend Supplies by Getting More Minerals from the Ocean? (2) Hydrothermal ore deposits Metals from the ocean floor: manganese nodules • Effect of mining on aquatic life • Environmental impact 14-5 How Can We Use Mineral Resources More Sustainability? Concept 14-5 We can try to find substitutes for scarce resources, reduce resource waste, and recycle and reuse minerals We Can Find Substitutes for Some Scarce Mineral Resources (1) Materials revolution Nanotechnology Silicon High-strength plastics • Drawbacks? We Can Find Substitutes for Some Scarce Mineral Resources (2) Substitution is not a cure-all • Pt: industrial catalyst • Cr: essential ingredient of stainless steel We Can Recycle and Reuse Valuable Metals Recycling • Lower environmental impact than mining and processing metals from ores Reuse There Are Many Ways to Use Mineral Resources More Sustainability How can we decrease our use and waste of mineral resources? Pollution and waste prevention programs • Pollution Prevention Pays (3P) • Cleaner production Solutions: Sustainable Use of Nonrenewable Minerals Case Study: Industrial Ecosystems: Copying Nature Mimic nature: recycle and reuse most minerals and chemicals Resource exchange webs Ecoindustrial parks Industrial forms of biomimicry • Benefits Solutions: An Industrial Ecosystem in Denmark Mimics Natural Food Web Sludge Pharmaceutical plant Local farmers Sludge Greenhouses Waste heat Waste heat Waste heat Fish farming Waste heat Oil refinery Surplus natural Electric power plant gas Surplus sulfur Surplus natural gas Waste calcium sulfate Fly ash Waste Cement manufacturer heat Sulfuric acid producer Wallboard factory Area homes Fig 14-25, p 367 [...]... flow Central vent Landslide Magma conduit Magma reservoir Solid phere s litho lten o m ally Parti osphere n asthe in g l l e Upw ma m ag Fig 14-7, p 349 Earthquakes Are Geological Rock-andRoll Events (1) Earthquake • • • • • Seismic waves Focus Epicenter Magnitude Amplitude Earthquakes Are Geological Rock-andRoll Events (2) Richter scale • • • • • • Insignificant:
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