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Chapter 16

Chapter 16. Mining & Mineral Resources. 16-1 Minerals & Mineral Resources. Almost every solid object is made of minerals Problem is obtaining enough minerals for a growing world population with minimal cost to the environment. Destruction from Mining. What is a Mineral?. Natural

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Chapter 16

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  1. Chapter 16 Mining & Mineral Resources

  2. 16-1 Minerals & Mineral Resources • Almost every solid object is made of minerals • Problem is obtaining enough minerals for a growing world population with minimal cost to the environment

  3. Destruction from Mining

  4. What is a Mineral? • Natural • Usually inorganic solid • Particular chemical structure • Particular set of physical properties • Made up of a single element or a compound • Atoms are arranged in a regular, repeating pattern

  5. Ore Minerals • Valuable • Economical to extract • Value of mineral must exceed cost of extraction and refining • Metallic • Shiny, conductors, opaque • Native elements such as gold, silver, copper • Nonmetallic • Insulators, usually dull, may be translucent • Are compounds or native elements

  6. Gangue minerals • Have no economical value • Are separated from ore minerals during extraction process

  7. How Do Minerals Form? • On and below earth • Depends on environmental conditions • Hydrothermal Solutions • Hot, subsurface waters containing dissolved minerals • Flows through cracks in rocks and crystallizes • Evaporites • Dissolved by rivers, carried to seas/lakes • When water evaporates, they are left behind (especially rock salt – halite)

  8. Mineral Resources & Uses • Metals or alloys (combinations of metals) have major economic and industrial importance • Nonmetals used in: • Construction of buildings and roads • Glassmaking • Computer chips • Gemstones

  9. 16-2 Mineral Exploration & Mining • Exploration is how mining companies decide where they will likely find high concentrations of minerals • Planes collect data about gravity and magnetism and take photographs • Rock samples provide additional data • Once information is gathered, companies decide if it is profitable to mine

  10. Subsurface Mining • 50m or more below earth’s surface • Seam: horizontal layer of coal • Room-and-pillar: entries are cut into a seam with pillars of coal left to support the roof • Longwall: coal is sheared from a 300m wall and transported by conveyor • Solution mining: Hot water injected into vein to dissolve minerals. Air bubbles bring it to the surface

  11. Surface Mining • Ore located close to the surface • Open pit: mined downward layer by layer (may be opened by explosives) and haul trucks transport it • Quarrying: removal of large rocks • Solar evaporation: sea water is evaporated in pools allowing salt to be left behind. Produces 30% of the earth’s salt

  12. Placer Mining • Surface deposits left when rock weathers • Materials carried away and concentrated by rivers or wave action

  13. Smelting • Crushed ore is melted and purified • Flux bonds with impurities and removed them

  14. Undersea Mining • Unsuccessful due to expense

  15. 16-3 Mining Regulations/Reclamation • Mining has become one of the most heavily regulated industries in the U.S. • More people more energy more fuel more miningmore damage • Reclamation – returning the land to its original condition

  16. The Environmental Impacts of Mining

  17. Air & Noise Pollution • Noise • Equipment • Explosions • Air • Dust • What’s being done? • Mining not near urban areas • Dust/noise prohibited from leaving mining area

  18. Water Contamination • Water seeps into mines dissolving toxins and carrying them to aquatic ecosystems • Acid Mine Drainage (AMD) – sulfur picked up reacts with oxygen in water to form acid • What’s Being Done? • Disposal of acid producing rock

  19. Wildlife Displacement • Removal of vegetation which causes all wildlife to leave • What’s being done? • Reclamation plan to bring back native plants and animals

  20. Erosion/Sedimentation • Excess rock dumped and sediment carried to streams where it damages water

  21. Soil Degradation • Soil is removed • Sometimes its not replaced properly so nutrients are disturbed • What’s being done? • Soil layers stored separately and replaced in correct order

  22. Subsidence • Sinking of ground above mines • Locations of many old mines are not known • Caused by lightening, forest fires and other forms of burning • Serious problem Underground Mine Fires

  23. Regulation/Reclamation • Surface Mining Control and Reclamation Act of 1977 – Created a program for regulating surface mining • States have individual regulations • Permits • Bond ($$) must be posted before mining begins • Fines for noncompliance

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