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14-2 How Are the Earth’s Rocks Recycled? • Concept 14-2 The three major types of rocks found in the earth’s crust—sedimentary, igneous, and metamorphic—are recycled very slowly by the process of erosion, melting, and metamorphism. There Are Three Major Types of Rocks (1) • The earth’s crust consists mainly of rocks and minerals… • Minerals - ________________ or inorganic element compound ______________ in earth’s crust • Usually a crystalline _______________, which has solid regular and repeating arrangement of atoms • Examples: gold, mercury, salt, quartz • Rock - solid _________________ of one or more combination minerals • Examples: limestone, quartzite, granite There Are Three Major Types of Rocks (2) sediments 1. Sedimentary rock – made of _________________ from dead plant and animal remains and tiny particles of weathered and eroded rocks layers • Deposited in ________________ and compacted • Increasing ______________ overtime converts them to pressure rock • Examples…Sandstone, Shale, Dolomite, Limestone, Lignite, Bituminous coal Sedimentary Rock Sandstone limestone There Are Three Major Types of Rocks (3) 2. Igneous rock - Forms below or at earth’s surface when magma ______________ wells up, cools and hardens • Form the ____________ of earth’s crust but are usually covered bulk by sedimentary rock • Examples: Granite, Lava rocks Igneous Rock granite pumice basalt 3. Metamorphic rock – forms when preexisting rock is subjected to high pressures, ______________ high temperatures, and/or chemically active fluids • Examples: Anthracite, Slate, Marble Metamorphic rock Slate, marble, gneiss, quartzite The Earth’s Rocks Are Recycled Very Slowly • Rock cycle – The interaction of physical and chemical change processes that ____________ rocks from one type to another Slowest • ______________ of the earth’s cyclic processes • Plays a major role in forming concentrated deposits of mineral ________________ resources Erosion Transportation Weathering Deposition Igneous rock Granite, pumice, basalt Sedimentary rock Sandstone, limestone Heat, pressure Cooling Heat, pressure, stress Magma (molten rock) Melting Metamorphic rock Slate, marble, gneiss, quartzite Fig. 14-10, p. 354 14-3 What Are Mineral Resources, and What Are their Environmental Effects? • Concept 14-3 We can make some minerals in the earth’s crust into useful products, but extracting and using these resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil. We Use a Variety of Nonrenewable Mineral Resources (1) naturally • A mineral resource is a concentration of _________________ occurring material from the earth’s crust that can be ___________________ from earth’s crust and processed into extracted _________ ________________ raw materials and products at an affordable cost • _________________ minerals – like gold and aluminum Metallic • ____________________ minerals – like sand and limestone Nonmetallic • Because minerals and rocks take so long to form, they are nonrenewable classified as _____________________ resources We Use a Variety of Nonrenewable Mineral Resources (1) • An ____________ ore is rock that contains a large enough concentration of particular mineral – often a metal – to make it ______________________ for mining and processing profitable • High-grade ore – contains a ________________ concentration large • Low-grade ore - contains a ______________ smaller concentration We Use a Variety of Nonrenewable Mineral Resources (2) • Metallic mineral resources • Aluminum (Al) – used for packaging and beverage cans ________; structural material in motor vehicles, aircrafts and buildings steel • Iron (Fe) – essential for ______________; buildings and motor vehicles wiring • Copper (Cu) – electrical and communication ___________ electrical • Gold (Au) – used in ________________ equipment, tooth jewelry fillings, ________________, coins, and some medical implants We Use a Variety of Nonrenewable Mineral Resources (2) • Nonmetallic mineral resources SiO2 glass • Sand (mostly ______) – used to make ____________, bricks and concrete roadbeds • Gravel – used for _______________ and to make concrete CaCO3 – crushed to make • Limestone (mostly _______) cement concrete and ______________ fertilizers • Phosphate salts – used for inorganic ______________ and some detergents We Use a Variety of Nonrenewable Mineral Resources (2) • The estimated supply of a mineral resource is called reserve a ________________ • Reserves can increase when… found • new deposits are _____________ technologies • Improved mining _____________________ make it more profitable to extract deposits Some Environmental Impacts of Mineral Use • While we can produce many useful products from mined resources, many disadvantages are related to the entire _______________ of a metal life cycle Surface mining Metal ore Separation of ore from gangue Smelting Melting metal Recycling Conversion to product Discarding of product Natural Capital Degradation Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources Steps Environmental Effects Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Exploration, extraction Processing Transportation, purification, manufacturing Use Transportation or transmission to individual user, eventual use, and discarding Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Fig. 14-12, p. 356 There Are Several Ways to Remove Mineral Deposits (1) • Surface mining shallow • Used to remove ________________ deposits vegetation • Begins with the removal of all __________________ covering the site overburden is removed… • Then the __________________ • soil and rock covering the useful mineral deposits spoils • Deposited in waste piles called _______________ There Are Several Ways to Remove Mineral Deposits (2) • Type of surface mining used depends on the ______________ resource and local _____________________ topography • Types of surface mining Open-pit • _________________ mining • machines dig very larger holes Strip • __________ mining • useful for deposits that lie in large _________________ horizontal beds Area • _________________ strip mining: flat surfaces Contour • _________________ strip: hilly or mountainous terrains Mountaintop • _______________________ removal • Removes the tops of mountains Natural Capital Degradation: Open-Pit Mine in Arizona Scarring and _______________________ degradation of the land surface Fig. 14-13, p. 357 Area Strip Mining in Wyoming Fig. 14-14, p. 357 Spoils Banks in Germany from Area Strip Mining Fig. 14-16, p. 358 banks • Strip mining often leaves spoil ___________ • Susceptible to erosion • Regrowth of vegetation is slow due to the lack of topsoil Spoil banks Mountaintop Coal Mining in West Virginia Waste is deposited into ________________ valleys below the mountaintops buried Streams are ______________; waste water and toxic sludge are often stored in _____________ in these valleys which can collapse and dams over flow Daily blasting exposes people dust to ____________ and can damage groundwater _______________ supplies Fig. 14-17, p. 359 Individuals Matter: Maria Gunnoe • Maria Gunnoe • West Virginia environmental activist…national public speaker Goldman • won a _________________ Environmental Prize in 2009 for her efforts to fight against mountaintop coal mining $150,000 • Cash prize of ________________ • Her home… • Flooded _______ times 7 yard • Toxic coal sludge in ______________ well • Groundwater and ___________ was contaminated Ecological Restoration of a Mining Site in Indonesia Surface mining sites can be restored but it is costly ___________ U.S. Department of the Interior, DOI _________, estimates that cleaning all U.S. sites would cost taxpayers $ 70 billion ______________ Fig. 14-18, p. 360 Mining Has Harmful Environmental Effects (2) • Subsurface mining deep • Used to remove __________________ deposits through tunnels and shafts cave-ins • Creates hazards such as _________________, explosions, and fires • Miners often get _________________ black lung - caused by prolonged inhalation of coal dust • Subsidence - _________________ land can affect communities sinking above mines Removing Metals from Ores Has Harmful Environmental Effects (1) • Ore extracted by mining typically has two components… • Ore mineral containing the ________________ metal desired • waste material called ___________________ gangue • The waste material is left in piles called _______________....toxic tailings particles can be blown by the wind or leached by rainfall Removing Metals from Ores Has Harmful Environmental Effects (1) • Heat or chemical solvents must be used to extract metals from ores smelting • Process called ________________________ • Without effective pollution control equipment, smelters emit air enormous amounts of __________ pollution liquid • Also produces ________________ and solid ________________ hazardous wastes Removing Metals from Ores Has Harmful Environmental Effects (2) • Core Case Study: highly toxic cyanide salt is used to extract gold from its ore • After extracting the gold from a mine, some mining bankruptcy so companies deliberately declare ______________ that they can avoid cleaning up their sites Colorado • Summitville gold mine: _________________, U.S. • Toxic waste site • Cleanup by the EPA will cost U.S. taxpayers about __________________ $120 million Tropical Gold Mining • Since the 1980s, millions of miners have streamed in tropical rivers to search for gold • Dig large ___________ and dredge pits ________________ from rivers sediment • Some use _________________ hydraulic mining (currently cannons outlawed in the U.S.) in which water _____________ wash entire hillsides into collection boxes Mercury • _______________ is also illegally used to separate gold from stream sediment • Nearby fish populations have dropped • Nearby villages suffer from mercury poisoning Review Questions! • Identify the types of rock formed throughout the rock cycle… Erosion Transportation Weathering Deposition igneous sedimentary Heat, pressure Heat, pressure, stress metamorphic Magma Review Questions! • What are some examples of… • metallic mineral resources? Aluminum, iron, copper, gold • nonmetallic mineral resources? Sand, limestone, gravel, phosphate salts • After an ore is acquired, what must be done to get the desired metal? Separate ore from waste (gangue) Heat or use chemicals (smelting) to get metal Review Questions! • Identify the types of surface mining shown below… Open pit mining Strip mining Mountain-top removal
