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Chapter 23 Materials management

Chapter 23 Materials management. Resource use. How much is left?. Mining. Is used to extract valuable minerals from the earth Is dependent on crustal abundance Elements and minerals are not equally represented or distributed in the earth’s crust Countries and companies have mineral reserves

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Chapter 23 Materials management

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  1. Chapter 23Materials management

  2. Resource use

  3. How much is left?

  4. Mining • Is used to extract valuable minerals from the earth • Is dependent on crustal abundance • Elements and minerals are not equally represented or distributed in the earth’s crust • Countries and companies have mineral reserves • Known quantity that can be realistically recovered by mining Relative crustal abundance of most common minerals

  5. Mined Materials • Sand and gravel • Metals • Phosphates • Salts • Sodium • Sulfur • Gemstones • Fuel sources • Coal • Uranium

  6. Ore • Concentrated accumulations of minerals formed from geologic processes • Can also contain waste material • Must usually be processed to produce a pure form of the mineral • Can occur in veins • Localized high concentrations of a mineral • Can occur in disseminated deposits • Large, widely spread lower concentrations of a mineral

  7. Types of Mining • Surface Mining • Placer • Strip • Mountaintop Removal • Open Pit • Subsurface Mining • Shaft • Solution • Ocean Mining

  8. Placer Mining • Used when a resource accumulates in riverbed deposits • Running water is used to sift lighter materials from the heavier resource materials • Also called panning • Disturbs large amounts of sediment

  9. Strip Mining • Used when a resource exists in layers near the Earth’s surface • Rock and soil above the resource (overburden) is removed from a strip of land • Mined material is removed and overburden is replaced

  10. Mountaintop Mining • Used when a resource occurs in seams near mountain ridges • Entire mountaintops are bulldozed and blasted away to reveal the seam • Overburden is replaced on the remaining mountain, and may fall or be dumped into adjacent valleys

  11. Open Pit Mining • Used when a resource is in an area unsuitable for tunneling, or when it is spread evenly and close to the surface • Also called a quarry

  12. Subsurface Mining • Used when a resource occurs deep underground • Vertical shafts are dug into the ground • Horizontal tunnels are dug to follow the seam or deposit being mined • Material is removed and sent to the surface for processing

  13. Solution Mining • Also called in-situ recovery • Used when a resource is buried deep, and can be dissolved in liquid • A hole is drilled to the resource, and water or acid is poured into the hole • The resource is sucked out and processed to remove it from the fluid

  14. Ocean Mining • Used when resource deposits exist on or under the sea floor, or in seawater • Resources are “vacuumed” off the sea floor • Research is underway to extract or evaporate resources from seawater

  15. Problems with Mining • All mining uses machinery and transportation that produces pollution • All mining produces tailings, or mineral waste that can damage ecosystems • The processing of ore can produce toxic byproducts • Extraction of gold uses cyanide • Miners are exposed to some of the most hazardous working conditions on the planet

  16. Acid Drainage • Most harmful form of environmental damage from mining • Occurs when newly exposed rock that contain sulfur reacts with water and oxygen to form sulfuric acid

  17. Acid Drainage • Sulfuric acid leaches metals from nearby rock and soil • Forms toxic acidic liquid called leachate • Cleanup involves neutralizing the acid and removing the metals

  18. Brownfields • Abandoned sites polluted with hazardous waste • Includes abandoned mines • Dangerous and difficult to clean up for reuse • Fall under EPA Superfund sites

  19. Mine Restoration or Reclamation • Goal is to restore a mined site to as close to its original condition as possible • Involves: • Filling in shafts and holes • Removing mining structures and equipment • Replacing overburden • Replanting • Ecosystems never fully recover from mining disruption

  20. General Mining Act of 1872 • Any individual or company can stake an exclusive claim on federal land open for mining • Land can be patented, or bought outright, for about $5/acre • No payments are made to the government, even if profits are realized • Includes gemstones, metals, uranium and minerals

  21. Mineral Leasing Act of 1920 • Public lands must be leased for mining, and royalties on profits are to be paid • Amounts depend on the resource being mined • Covers fossil fuels, sodium, sulfur, and phosphates

  22. Surface Mining Control and Reclamation Act of 1977 • Regulates the surface effects of coal mining • Mandates reclamation of mined areas

  23. Minerals are Nonrenewable • Minerals regenerate slowly • Many mineral deposits are being mined very quickly • As they become scarce, they will become more expensive • Environmentally friendly alternatives are being sought, including recycling

  24. Sustainable Mineral Use • Recycling is the best way to sustainably use many minerals • Uses less energy in production of goods • Reduces the amount of mining • Recycling e-waste is especially important • Reducing the use of products that contain minerals also helps

  25. Waste • Anything not useful or consumable • Is the product of a system • Inputs are raw materials and/or energy • Outputs are useful products, recyclable products, and waste

  26. A Culture of Waste • In the 1950s it became culturally acceptable to throw things away • Labor-saving, disposable consumer goods were developed • Planned obsolescence became a part of life • Products designed to be replaced

  27. Municipal Solid Waste • Is waste from non-industrial, non-agricultural, non-mining sources • Includes residences and businesses • 60% is from residences • Average is 2.8 (4.5 lbs) kg/person/day

  28. E-Waste • Is only 2% of the waste stream, but is increasing • Has an environmental impact greater than its small percentage implies • Contain metals and acids that are harmful • Poor disposal can release these pollutants to the environment • Recycling of this material must be done carefully

  29. Decreasing the Impact of Waste • Includes implementing the three R’s • Reduce, reuse, recycle • Includes composting

  30. Landfills • Are the most common waste disposal method • Basically just a hole in the ground filled with trash • Are a better option than open dumps • There is some control over what goes in a landfill • Can generate leachate • Water runs through the landfill and picks up chemicals from waste

  31. Sanitary Landfills • Are designed to minimize impact on surrounding areas • Are lined in plastic, often with a layer of clay beneath • Have pipes that are used to collect and remove leachate • Also have methane collection pipes • Methane can be burned to generate electricity or to power vehicles

  32. Sanitary Landfills • Are filled with materials that are: • Unlikely to create methane or toxic leachate • Difficult to recycle • Are closed once they are full • Capped with plastic • Covered in a layer of concrete or soil • Can be reclaimed for construction or parks

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