Geology and Nonrenewable Minerals Chapter 12

Key Concepts Major geologic processes Major geologic processes Rocks and the rock cycle Rocks and the rock cycle Finding and extracting mineral resources Finding and extracting mineral resources Environmental effects of mining Environmental effects of mining Enough nonrenewable resources for the future? Enough nonrenewable resources for the future?

General Mining Law of 1872 Original purpose of the law Original purpose of the law Impact on US public lands Impact on US public lands Benefits to mining companies Benefits to mining companies Costs to the public Costs to the public Environmental issues Environmental issues Laws in other countries Laws in other countries Fig. 12-1, p. 269

Internal Geologic Processes What is geology? What is geology? - the study dynamic processes occurring on the Earth’s surface and in it’s interior. - the study dynamic processes occurring on the Earth’s surface and in it’s interior. Earth’s internal structure Earth’s internal structure Core - solid inner part, surrounded by a liquid core of semisolid material.Core - solid inner part, surrounded by a liquid core of semisolid material. Mantle - surrounds the core. Solid rock over the asthenosphers.Mantle - surrounds the core. Solid rock over the asthenosphers. Crusts (continental and oceanic)Crusts (continental and oceanic) Plate tectonics - convection cells cause about 15 plates to move across the earth’s surface. Plate tectonics - convection cells cause about 15 plates to move across the earth’s surface.

Atmosphere Biosphere Crust Lower mantle Asthenosphere Upper mantle Continental crust Oceanic crust Lithosphere Vegetation and animals Soil Rock Crust (soil and rock) Atmosphere (air) Biosphere (living and dead organisms) Lithosphere (crust, top of upper mantle) Hydrosphere (water) Core Mantle Fig. 3-5, p. 38 General Structure of the Earth

Fig. 12-2, p. 271 Oceanic crust (lithosphere) Abyssal hills Abyssal floor Oceanic ridge Trench Volcanoes Folded mountain belt Craton Mantle (lithosphere) Mantle (asthenosphere) Abyssal plain Continental crust (lithosphere) Mantle (lithosphere) Continental rise Continental slope Continental shelf Abyssal plain Abyssal floor Earth’s Crust and Upper Mantle

Fig. 12-3, p. 272 Tectonic plate Collision between two continents Oceanic tectonic plate Spreading center Oceanic tectonic plate Ocean trench Plate movement Continental crust Subduction zone Oceanic crust Oceanic crust Continental crust Mantle Inner core Hot outer core Two plates move towards each other. One is subducted back into the mantle on falling convection current. Mantle convection cell Hot material rising through the mantle Material cools as it reaches the outer mantle Cold dense material falls back through mantle Plate Tectonics Inner core

Plate Tectonics Tectonic plates Tectonic plates Lithosphere - outer most part of the mantel Lithosphere - outer most part of the mantel Plate tectonics and biological evolution Plate tectonics and biological evolution - Populations became isolated and speciation occurred. - Populations became isolated and speciation occurred.

Fig. 12-4, p. 273 EURASIAN PLATE CHINASUBPLATE PHILIPPINEPLATE INDIAN-AUSTRLIAN PLATE PACIFICPLATE JUAN DE FUCA PLATE NORTHAMERICAN PLATE PLATE SOUTHAMERICAN ANATOLIAN ARABIAN SOMALIAN SUBPLATE SUBPLATE ANTARCTIC PLATE Convergent plate boundariesDivergent boundaries Earth’s Major Tectonic Plates AFRICAN PLATE PLATE NAZCA CARIBBEAN Transform faults

Types of Plate Boundaries Divergent Divergent Move apart Move apart Convergent Convergent Pushed together Pushed together Transform Transform Grind past one another Grind past one another Fig. 12-5, p. 274

Fig. 12-5a, p. 274 Lithosphere Asthenosphere Oceanic ridge at a divergent plate boundary Types of Plate Boundaries

Fig. 12-5b, p. 274 Lithosphere Trench Volcanic island arc Asthenosphere Rising magma Subduction zone Trench and volcanic island arc at a convergent plate boundary Types of Plate Boundaries

Transform fault connecting two divergent plate boundaries Fig. 12-5c, p. 274 Fracture zone Transform fault Lithosphere Asthenosphere Types of Plate Boundaries

External Earth Processes Erosion Erosion - material is dissolved, loosened, or worn away - material is dissolved, loosened, or worn away Physical (mechanical) weathering: frost wedging Physical (mechanical) weathering: frost wedging Chemical weathering Chemical weathering Biological weathering Biological weathering

Question of the Day As the Tsunami crest approaches shore, the wave height _________, the velocity __________, and the period _____. Choices: Decreases Increases Increases Remains constant Remains constant

Fig. 12-6, p. 275 Igneous Rock Granite, pumice, basalt Metamorphic Rock Slate, marble, gneiss quartzite Magma (molten rock) Heat, pressure, stress Heat, pressure Melting Sedimentary Rock sandstone, limestone Deposition Transportation Erosion Weathering The Rock Cycle Cooling

Mineral Resources Generally nonrenewable Generally nonrenewable Metallic, nonmetallic, and energy resources Metallic, nonmetallic, and energy resources Ores - rock containing enough of one or more metallic minerals to be mined profitably. Ores - rock containing enough of one or more metallic minerals to be mined profitably.

Categories of Mineral Resources Identified Identified Undiscovered Undiscovered Reserves Reserves Other Other Fig. 12-7, p. 276

Finding Mineral Resources Aerial and satellite images Aerial and satellite images Radiation detectors Radiation detectors Magnetometers Magnetometers Gravimeters Gravimeters Seismic surveys Seismic surveys Chemical analyses Chemical analyses

Extracting Mineral Deposits Surface mining Surface mining Subsurface mining Subsurface mining Overburden - soil and rock Overburden - soil and rock Spoils - discarded overburden or waste material Spoils - discarded overburden or waste material

Mining Methods Open-pit (surface mining) Bingham Utah Open-pit (surface mining) Bingham Utah Area strip mining (surface) Area strip mining (surface) Contour strip mining (surface) Contour strip mining (surface) Mountaintop removal (surface) Mountaintop removal (surface) The Surface Mining Control and Reclamation Act of 1977 The Surface Mining Control and Reclamation Act of 1977 Subsurface mining Subsurface mining Hazards and environmental tradeoffs of subsurface mining Hazards and environmental tradeoffs of subsurface mining

Open-pit Mine Fig. 12-8, p. 277

Spoil from an Unrestored Area Strip Mine Fig. 12-9, p. 277

Highwall Coal seam Overburden Coal seam Pit Bench Undisturbed Land Overburden Spoil Banks Contour Strip Mining Fig , p. 277

Mountaintop Mining Fig , p. 278

Environmental Effects of Using Mineral Resources Disrupting the land surface Disrupting the land surface Subsidence Subsidence Toxic mining waste Toxic mining waste Acid mine drainage Acid mine drainage Air pollution Air pollution Toxic holding ponds Toxic holding ponds

StepsEnvironmental Effects Exploration, extraction Mining Disturbed land; mining accidents; health hazards; mine waste dumping;oil spills and blowouts; noise; ugliness; heat Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing Transportation, purifi- cation, manufacturing Use transportation or trans- mission to individual user, eventual use, and discarding Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Fig , p. 279 Environmental Effects of Mineral Use Natural Capital Degredation Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources

Processing of Mineral Resources Ore mineral - the desired metal Ore mineral - the desired metal Gangue - (“gang”) the waste material Gangue - (“gang”) the waste material Tailings - piles of waste produced by processing Tailings - piles of waste produced by processing Smelting - separates the metal from other elements in the ore mineral Smelting - separates the metal from other elements in the ore mineral Products Products Disposal or recycling Disposal or recycling

Surface mining Metal ore Separation of ore from gangue Recycling Discarding of product (Scattered in environ- ment) Conversion to product Melting metal Smelting Fig , p. 279 Typical Life Cycle of a Metal Resource Reuse

Environmental Limits to Resource Extraction Environmental damage: a major mining problem which will limit their availability, not exhaustion of supplies Environmental damage: a major mining problem which will limit their availability, not exhaustion of supplies Ore grade - higher-grade ores exploited first Ore grade - higher-grade ores exploited first Including environmental costs in products Including environmental costs in products

Supplies of Mineral Resources Available supply and how rapidly it is used Available supply and how rapidly it is used Minerals become “Economically depletion” not “totally depleted” Minerals become “Economically depletion” not “totally depleted” Five choices after depletion Five choices after depletion Recycle or reuseRecycle or reuse Waste lessWaste less Use lessUse less Find a substituteFind a substitute Do withoutDo without Depletion time is how long it takes to use 80% of the reserves Depletion time is how long it takes to use 80% of the reserves Economics determines what part of the known supply is extracted and used Economics determines what part of the known supply is extracted and used Finding alternatives Finding alternatives

Fig , p. 280 PresentDepletion time A Depletion time B Depletion time C Time Production C B A Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries Recycle; increase reserves by improved mining technology, higher prices, and new discoveries Mine, use, throw away; no new discoveries; rising prices Depletion Curves for a Nonrenewable Resource

Economics and Supplies of Nonrenewable Resources Roll of economics in mining Roll of economics in mining Standard economic theory = supply and demand Standard economic theory = supply and demand Limited free market in developed countries Limited free market in developed countries Government subsidies of mining Government subsidies of mining 1872 US General Mining Law 1872 US General Mining Law Economic problems of developing new mines Economic problems of developing new mines

Mining Lower-grade Ores New extraction technologies are needed New extraction technologies are needed Factors that limit mining lower-grade ores Factors that limit mining lower-grade ores CostsCosts Supplies of freshwaterSupplies of freshwater Environmental impactsEnvironmental impacts Biomining: microorganisms and in-situ mining Biomining: microorganisms and in-situ mining

Nanotechnology Revolution Nanotechnology Nanotechnology Buckyballs Buckyballs Molecular economy Molecular economy Possible achievements of nanotechnology Possible achievements of nanotechnology Possible environmental and health threats Possible environmental and health threats Likely need for guidelines and regulations Likely need for guidelines and regulations

Ocean Mining Ore deposits in the ocean Ore deposits in the ocean Minerals from seawater Minerals from seawater Minerals in ocean sediments Minerals in ocean sediments Hydrothermal deposits Hydrothermal deposits Manganese-rich nodules Manganese-rich nodules Mining issues in international waters Mining issues in international waters Environmental issues Environmental issues

Fig , p. 283 Magma Black smoker Sulfide deposit White crab Tube worms White smoker White clam Hydrothermal Ore Deposits on the Ocean Floor

Finding Substitutes for Scarce Mineral Resources Materials revolution Materials revolution Ceramic substitutes Ceramic substitutes High-strength plastics and composites High-strength plastics and composites Finding some substitutes may be impossible Finding some substitutes may be impossible Some substitutes are inferior Some substitutes are inferior