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Nonrenewable Mineral Resources
14 Nonrenewable Mineral Resources
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Core Case Study: The Crucial Importance of Rare-Earth Metals
Crucial to the technologies that support today’s lifestyles and economies Used to make LCDs, LED light bulbs, fiber optic cables, cell phones, and digital cameras Without affordable supplies of rare earth elements, we could not develop cleaner technologies
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Electric motors and generator • Dysprosium • Neodymium
Catalytic converter • Cerium • Lanthanum Battery • Lanthanum • Cerium LCD screen • Europium • Yttrium • Cerium Figure 14-2: Manufacturers of all-electric and hybrid-electric cars use a variety of rare earth metals. Electric motors and generator • Dysprosium • Neodymium • Praseodymium • Terbium Fig. 14-2, p. 350
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14-1 What Are the Earth’s Major Geological Processes/Mineral Resources?
Dynamic processes within the earth and on its surface produce the mineral resources on which we depend Mineral resources are nonrenewable Produced and renewed over millions of years mostly by the earth’s rock cycle
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The Earth Is a Dynamic Planet
Geology Study of dynamic processes taking place on earth’s surface and in earth’s interior Three major concentric zones of the earth Core Mantle, including the asthenosphere Crust Continental crust Oceanic crust: 71% of crust
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Cold dense material falls back through mantle Mantle convection cell
Spreading center Oceanic tectonic plate Collision between two continents Oceanic tectonic plate Plate movement Plate movement Tectonic plate Oceanic crust Oceanic crust Continental crust Continental crust Cold dense material falls back through mantle Material cools as it reaches the outer mantle Hot material rising through the mantle Mantle convection cell Asthenosphere Figure 14-3: The earth is composed of a core, mantle, and crust, and within the core and mantle, dynamic forces have major effects on what happens in the crust and on the surface. Two plates move towards each other. One is subducted back into the mantle on a falling convection current. Mantle Hot outer core Inner core Fig. 14-3, p. 351
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What Are Minerals and Rocks?
Naturally occurring compound that exists as a crystalline solid Mineral resource Concentration that we can extract and process into raw materials Rock Solid combination of one or more minerals
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What Are Minerals and Rocks? (cont’d.)
Sedimentary rock Made of sediments Dead plant and animal remains Tiny particles of weathered and eroded rocks Igneous rock Intense heat and pressure Metamorphic rock Existing rock subjected to high temperatures, pressures, fluids, or a combination
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Earth’s Rocks Are Recycled Very Slowly
Rock cycle Rocks are recycled over millions of years Erosion, melting, and metamorphism Slowest of earth’s cycle processes
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We Depend on a Variety of Nonrenewable Mineral Resources
Ore Contains profitable concentration of a mineral High-grade ore Low-grade ore Metallic mineral resources Aluminum Iron for steel Copper
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We Depend on a Variety of Nonrenewable Mineral Resources (cont’d.)
Nonmetallic mineral resources Sand, gravel, and limestone Reserves Estimated supply of a mineral resource
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Igneous rock Granite, pumice, basalt
Erosion Transportation Weathering Deposition Igneous rock Granite, pumice, basalt Sedimentary rock Sandstone, limestone Heat, pressure Cooling Heat, pressure, stress Magma (molten rock) Figure 14-5: Natural capital: The rock cycle is the slowest of the earth’s cyclical processes. Melting Metamorphic rock Slate, marble, gneiss, quartzite Fig. 14-5, p. 353
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How Long Might Supplies of Nonrenewable Mineral Resources Last?
Nonrenewable mineral resources exist in finite amounts Can become economically depleted when it costs more than it is worth to find, extract, and process the remaining deposits There are several ways to extend supplies of mineral resources But each of these is limited by economic and environmental factors
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Supplies of Nonrenewable Mineral Resources Can Be Economically Depleted
Reserves Identified deposits from which we can extract the mineral profitably Depletion time Time to use a certain portion of reserves
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Nonrenewable Mineral Resources Can Be Economically Depleted (cont’d.)
When a resource becomes economically depleted: Recycle or reuse existing supplies Waste less Use less Find a substitute Do without
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Depletion time A Depletion time B Depletion time C
Mine, use, throw away; no new discoveries; rising prices Depletion time A Recycle; increase reserves by improved mining technology, higher prices, and new discoveries B Depletion time B Production Recycle, reuse, reduce consumption; increase reserves by improved mining technology, higher prices, and new discoveries C Depletion time C Figure 14-6: Natural capital depletion: Each of these depletion curves for a mineral resource (such as aluminum, copper, or a rare earth) is based on a different set of assumptions. Dashed vertical lines represent the times at which 80% depletion occurs. Present Time Stepped Art Fig. 14-6, p. 360
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Global and U.S. Rare-Earth Supplies
Rare-earth elements aren’t really rare China produces 97% of the world’s rare- earth metals and oxides The U.S. produces none
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Market Prices Affect Supplies of Nonrenewable Minerals
Subsidies and tax breaks to mining companies keep mineral prices artificially low Scarce investment capital hinders the development of new supplies of mineral resources
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Can We Expand Reserves by Mining Lower-Grade Ores?
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 Using microorganisms – biomining Slow process
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Can We Get More Minerals from the Ocean?
Mineral resources dissolved in the ocean Low concentrations Deposits of minerals in sediments along the shallow continental shelf and near shorelines
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Can We Get More Minerals from the Ocean? (cont’d.)
Hydrothermal ore deposits Hot water vents in the ocean floor Metals from the ocean floor Manganese nodules What is the effect of mining on aquatic life?
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Black smoker White smoker Sulfide deposits Magma White clam White crab
Figure 14-8: Natural capital. Hydrothermal deposits, or black smokers, are rich in various minerals. White clam White crab Tube worms Fig. 14-8, p. 356
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14-3 What Are The Environmental Effects From Using Nonrenewable Minerals?
Extracting minerals from the earth’s crust and converting them into useful products can: Disturb the land Erode soils Produce large amounts of solid waste Pollute the air, water, and soil
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Mineral Use Creates Environmental Impacts
Metal product life cycle Mining, processing, manufacture, and disposal Environmental impacts Determined by an ore’s grade Percentage of metal content
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Separation of ore from waste material Smelting Melting metal
Mining Metal ore Separation of ore from waste material Smelting Melting metal Conversion to product Discarding of product Recycling Figure 14-9: Each metal product that we use has a life cycle. Fig. 14-9, p. 357
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Removing Mineral Deposits Has Harmful Environmental Effects
Surface mining Removes shallow deposits Overburden deposited into spoils – waste material Open-pit mining Strip mining Contour strip mining Mountaintop removal
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Figure 14-10: Natural capital degradation: This spoils pile in Zielitz, Germany, is made up of waste material from the mining of potassium salts used to make fertilizers. Fig , p. 358
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Figure 14-11: Natural capital degradation: Kennecott’s Bingham Canyon Mine in the U.S. state of Utah has produced more copper than any mine in history. This gigantic open-pit mine is almost 5 kilometers (3 miles) wide and 1,200 meters (4,000 feet) deep, and it is getting deeper. Fig , p. 358
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Undisturbed land Overburden Highwall Coal seam Overburden Pit Bench
Figure 14-13: Natural capital degradation: Contour strip mining is used in hilly or mountainous terrain. Spoil banks Fig , p. 359
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Removing Mineral Deposits Has Harmful Environmental Effects (cont’d.)
Subsurface mining Deep deposits Potential problems Subsidence Acid mine drainage
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Figure 14-15: Acid mine drainage from an abandoned open-pit coal mine in Portugal.
Fig , p. 360
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Case Study: The Real Cost of Gold
At about 90% of the world’s gold mines Mineral extracted with cyanide salts Cyanide is extremely toxic Mining companies declare bankruptcy Allows them to avoid environmental remediation
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Removing Metals from Ores Has Harmful Environmental Effects
Ore extracted by mining Ore mineral Tailings – waste material Smelting using heat or chemicals causes: Air pollution Water pollution
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14-4 How Can We Use Mineral Resources More Sustainability?
We can: Try to find substitutes for scarce resources Reduce resource waste Recycle and reuse minerals
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We Can Find Substitutes for Some Scarce Mineral Resources
Materials revolution Silicon replacing some metals for common uses New technologies: Nanotechnology, ceramics, and high-strength plastics Substitution doesn’t always work Platinum – industrial catalyst
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We Can Use Mineral Resources More Sustainably
Recycling and reuse Lower environmental impact than mining and processing metals from ores Adequate supplies of rare-earth elements in the short-term Substitutes for rare-earth elements
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Solutions: Sustainable Use of Nonrenewable Minerals
Figure 14-17: We can use nonrenewable mineral resources more sustainably (Concept 14-4). Questions: Which two of these solutions do you think are the most important? Why? Fig , p. 364
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14-5 What Are the Earth’s Major Geologic Hazards?
Dynamic processes move matter within the earth and on its surface and can cause volcanic eruptions, earthquakes, tsunamis, erosion, and landslides
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The Earth Beneath Your Feet Is Moving
The earth’s crust is broken into tectonic plates “Float” on the asthenosphere Much geological activity takes place at the plate boundaries
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Indian-Australian plate
North American plate Eurasian plate Juan De Fuca plate Caribbean plate Philippine plate Arabian plate Cocos Plate Pacific plate African plate Pacific plate Indian-Australian plate South American plate Nazca plate Figure 14-18: The earth’s crust has been fractured into several major tectonic plates. White arrows indicate examples of where plates are colliding, separating, or grinding along against each other in opposite directions. Question: Which plate are you riding on? Antarctic plate Scotia plate Fig , p. 366
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Volcanoes Release Molten Rock from the Earth’s Interior
Magma rising through the lithosphere reaches the earth’s surface through a crack Eruption – release of lava, hot ash, and gases into the environment What are the benefits and hazards of volcanoes?
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Extinct volcanoes Eruption cloud Ash Acid rain Ash flow Lava flow
Mud flow Central vent Landslide Magma conduit Figure 14-20: Sometimes, the internal pressure in a volcano is high enough to cause lava, ash, and gases to be ejected into the atmosphere (photo inset) or to flow over land, causing considerable damage. Magma reservoir Solid lithosphere Partially molten asthenosphere Upwelling magma Fig , p. 367
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Figure 14-20: Sometimes, the internal pressure in a volcano is high enough to cause lava, ash, and gases to be ejected into the atmosphere (photo inset) or to flow over land, causing considerable damage. Fig , p. 367
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Earthquakes Are Geological Rock-and-Roll Events
Breakage and shifting of rocks At a fault Seismic waves Vibrations in the crust Focus – origin of earthquake Magnitude – severity of earthquake Amplitude – size of the seismic waves
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Earthquakes Are Geological Rock-and-Roll Events (cont’d.)
Richter scale Insignificant: <4.0 Minor: 4.0–4.9 Damaging: 5.0–5.9 Destructive: 6.0–6.9 Major: 7.0–7.9 Great: >8.0 Largest recorded: 9.5 in Chile, 1960
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Figure 14-19: The San Andreas Fault, created by the North American Plate and the Pacific Plate sliding very slowly past each other, runs almost the full length of California (see map). It is responsible for earthquakes of various magnitudes, which have caused rifts on the land surface in some areas (photo). Fig , p. 366
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Liquefaction of recent sediments causes buildings to sink
Two adjoining plates move laterally along the fault line Earth movements cause flooding in low-lying areas Landslides may occur on hilly ground Figure 14-21: An earthquake (left) is one of nature’s most powerful events. The photo shows damage from a 2010 earthquake in Port-au-Prince, Haiti. Shock waves Focus Epicenter Fig , p. 367
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Figure 14-21: An earthquake (left) is one of nature’s most powerful events. The photo shows damage from a 2010 earthquake in Port-au-Prince, Haiti. Fig b, p. 367
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Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis
Series of huge waves generated when ocean floor suddenly rises or drops Travels several hundred miles per hour December 2004 – Indian Ocean tsunami Magnitude 9.15 and 31-meter waves at shore
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Earthquakes on the Ocean Floor Can Cause Huge Waves Called Tsunamis
2011 – Japan tsunami Damaged nuclear reactors Detection of tsunamis Buoys in open ocean
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Earthquake in seafloor swiftly pushes water upwards, and starts a series of waves
Waves move rapidly in deep ocean reaching speeds of up to 890 kilometers per hour. As the waves near land they slow to about 45 kilometers per hour but are squeezed upwards and increased in height. Waves head inland causing damage in their path. Figure 14-22: This diagram illustrates how a tsunami forms. The map shows the area affected by a large tsunami in December 2004—one of the largest ever recorded. Undersea thrust fault Fig a, p. 368
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Upward wave Earthquake
Figure 14-22: This diagram illustrates how a tsunami forms. The map shows the area affected by a large tsunami in December 2004—one of the largest ever recorded. Fig b, p. 368
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Three Big Ideas Dynamic forces that move matter within the earth:
Recycle the earth’s rocks Form deposits of mineral resources Cause volcanic eruptions, earthquakes, and tsunamis
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Three Big Ideas (cont’d.)
The available supply of a mineral resource depends on: How much of it is in the earth’s crust How fast we use it The mining technology used to obtain it Market prices Harmful environmental effects of removing and using it
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Three Big Ideas (cont’d.)
We can use mineral resources more sustainably by: Trying to find substitutes for scarce resources Reducing resource waste Reusing and recycling nonrenewable minerals
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Tying It All Together: Rare-Earth Metals and Sustainability
Rare-earth elements are important for a variety of modern technologies New technological developments can help extend mineral supplies Nanotechnology Biomining Graphene
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