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Op ch15 lecture_earth3, Mineral resources

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Mineral deposits can be classified as:Mineral resources that are potentially valuable, and for which reasonable prospects exist for eventual economic extraction.Mineral reserves or Ore reserves that ...

Mineral deposits can be classified as:Mineral resources that are potentially valuable, and for which reasonable prospects exist for eventual economic extraction.Mineral reserves or Ore reserves that are valuable and legally and economically and technically feasible to extract
In common mining terminology, an "ore deposit" by definition must have an 'ore reserve', and may or may not have additional 'resources'

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Op ch15 lecture_earth3, Mineral resources Presentation Transcript

  • 1. Chapter 15 Riches in Rock: Mineral Resources LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 2. Riches in Rock: Mineral Resources Prepared by Ronald Parker Earlham College Department of Geosciences Richmond, Indiana
  • 3. Mineral Resources  Minerals from the crust that are used by civilization. Minerals are present in almost everything we use.  They are utterly necessary for modern industrial society.   Two major categories. Metallic.  Nonmetallic.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 4. Mineral Resources  Mineral resources form by geologic processes. Occurrences are predictable.  Formation is usually very slow.   Minerals are effectively nonrenewable resources. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 5. Mineral Resources Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 6. Mineral Resources  Two major categories.  Metallic. Gold. Silver. Copper. Lead. Zinc. Iron. Aluminum.  Nonmetallic. Sand and gravel. Gypsum. Halite. Dimension stone. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 7. What Is a Metal? Opaque, shiny, smooth, conductive solids.  Metal properties from metallic chemical bonds.  Delocalized electrons move from atom to atom easily.  Electron fluidity creates electrical conductivity.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 8. What Is a Metal?  Properties due to crystal structure and bonding. Metals may be extremely hard (titanium) or soft (copper).  Ductile – Able to be drawn into thin wires.  Malleable – Able to be pounded into thin sheets.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 9. What Is a Metal?  3 categories.  Native – Naturally occur in pure form. Copper (Cu) Silver (Ag) Gold (Au)  Precious – Rare and economically important. Gold (Au) Silver (Ag) Platinum (Pt)  Base – Commonly used in industry. Iron (Fe) Lead (Pb) Zinc (Zn) Tin (Sn) Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 10. The Discovery of Metals Native metals occur naturally in a pure form.  Native metals are rare and durable. They include…  Gold.  Silver.  Copper.  Iron.   We have utilized native metals for 1,000s of years. Tools – They are easily shaped by cold working.  Money – Chosen because of rarity and durability.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 11. The Discovery of Metals  Quest for native metals important in human history. Native American copper trade.  Spanish Conquistadors.  California and Klondike gold.   Today, minerals underpin the wealth of nations. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 12. Metals Native metals are too rare to be mine sources.  Instead, we use minerals that contain metals.  Metal ions are bonded to non-metallic elements.  Ore minerals rarely resemble the pure metal.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 13. Smelting  Releases metals from the mineral.  Different minerals require… Different smelting techniques. Different temperatures.  Nonmetallic waste is called slag. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 14. Smelting Steel is made from iron smelted with carbon.  Blending molten metals creates alloys.  Alloy properties differ from pure metals.  Bronze – An alloy of copper and tin.  Brass – Copper alloyed with zinc.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 15. What Is an Ore?  Rock with a concentration of metal-rich minerals. Present in enough abundance to be economic to mine.  Metal must be readily extracted from the mineral.  There are many different ore minerals.   Ores form via geological processes. Magmatic activity.  Hydrothermal alteration.  Secondary enrichment.  Sedimentary processes.  Weathering processes.  Hydraulic sorting.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 16.  Common ore minerals. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 17. Ore Formation  Geologic processes often concentrate metals. Concentration must be high enough to yield a profit.  The amount of useful metal present is the ore grade.  The amount of enrichment required differs by metal.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 18. Ore Formation  Geologic processes generate mineral resources. A dominant control is exerted by plate tectonics.  Tectonic effects are overprinted by the hydrologic cycle.   Ore formation requires large amounts of time. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 19. Ore Formation Mineral resource occurrence is predictable.  Ores are not equitably distributed.  Some countries have many mineral resources.  Other countries lack resources.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 20. Ore Formation  Magmatic ores. Sulfide minerals crystallize early and sink in magma.  Form massive sulfide ores at the bottom of chamber.  Sulfides include…  Pyrite. Chalcopyrite. Bornite. Galena. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 21. Ore Formation  Hydrothermal deposits. Minerals deposited by hot, chemically active fluids.  Common in rocks heated by plutonic intrusions.  Often crystallize in rock fractures as vein deposits.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 22. Ore Formation  Hydrothermal deposits.  Black smokers - Occur along all mid-ocean ridges. Seawater in cracked hot crust is heated, picking up metals. Water cycles back to the cold ocean, metals crystallize out. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 23. Ore Formation  Hydrothermal deposits.  Mississippi Valley-type (MVT) ores. Orogenic belts “squeegee” hot water through deep basins. The hot water leaches minerals and carries them along. Where basin brines surface and cool, they deposit metals. MVT lead-zinc (Pb-Zn) deposits. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 24. Ore Formation  Secondary-enrichment deposits. Ground water leaches and oxidizes primary sulfide ores.  Adding O2, OH, and CO2, some secondary ores are prized.  Malachite. Azurite. Turquoise. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 25. Ore Formation  Sedimentary deposits.  Banded iron formations (BIFs). Layered specular hematite (Fe2O3) and red chert (jasper). Found globally 2.5 – 2 Ga with O2 buildup in atmosphere.  Manganese (MnO2 )–rich nodules. Rich in trace elements, these grow slowly on the seafloor Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 26. Ore Formation  Residual mineral deposits. Form via extreme (tropical) chemical weathering.  Intense weathering strips almost everything out of soil.  Residual lateritic soil is enriched in Fe and Al oxides.  Bauxite – Primary ore of aluminum. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 27. Ore Formation  Placer deposits – Concentrated by flowing water.  In high-velocity water… Low-density minerals are suspended and washed away. High-density grains are concentrated by settling out. Important for gold, tin, and iron.  Best preserved in fossil stream sediments.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 28. Mineral Exploration  Ores are located by evidence of metal enrichment. Color – Enrichment often discolors rock and soil.  Geophysical surveys – Magnetism, gravity, radioactivity.  Geochemical surveys – Ore can be found by chemical analyses of water, stream sediment, soil, and biota.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 29. Mineral Exploration  Ore present in a deposit is assessed by... Geophysical measurements.  Core drilling.  Geochemical analyses.   If economic, a deposit is developed for mining. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 30. Mineral Production Open-pit mines – Large excavations open to the air.  Less expensive and dangerous than tunnel mines.  Usually require ore within 100 m of the land surface.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 31. Mineral Production  Underground mines – Ore obtained by tunneling. Tunnels are linked to a vertical shaft (an adit).  Ore is removed by drilling and blasting.  Excavated ore is hauled to the surface for processing.  Expensive and dangerous.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 32. Nonmetallic Resources  Materials that lack metals are used by humans. Dimension stone – Rock slabs used as building material.  Crushed stone – Material for roads, asphalt, and concrete.  Cement – Mixture of heated limestone, quartz, and clay.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 33. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 34. Nonmetallic Resources  Nonmetallic minerals commonly used in homes. Calcite – Base material of cement (concrete).  Clay minerals – Used for bricks, pottery, dishware.  Gypsum – Most common material in wallboard or plaster.  Quartz – Used to make window glass.   U.S. per capita nonmetallic mineral use is huge. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 35. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 36. Global Mineral Needs  Mineral resources are nonrenewable. They form as the result of geologic processes.  These processes are too slow to generate new deposits.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 37. Global Mineral Needs  Mineral resources are not evenly distributed. Some countries are mineral-rich; some are mineral-poor.  This is a particular issue for strategic mineral resources.  Metals needed for highly specialized applications. National security and defense. Aerospace. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 38. Global Mineral Needs  How long will current mineral resources last?   Depends upon consumption rates and reserve amounts. Some mineral resources will run out soon. Global resources of Pb, Zn, and Au?  U.S. resources of Pt, Ni, Co, Mn, Cr?  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak < 30 years. <1 year. Chapter 15: Riches in Rock: Mineral Resources
  • 39. Global Mineral Needs  Continued use of scarce minerals will require… Discovery of new sources.  Increase in price to make hard-to-get reserves profitable.  Increased efficiency and conservation.  Substitution.  Recycling.  Doing without.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 40. Environmental Issues  Extraction and processing has large impacts. Air.  Surface water.  Ground water.  Soils.  Biota.  Aesthetics.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 41. Environmental Issues  Acid mine drainage (AMD).  Sulfides exposed to O2 create sulfuric acid. Water from spoil piles is acidified (pH < 5.7).  AMD creates toxic conditions.  Mobilizes heavy metals. Kills stream organisms. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 42. Environmental Issues Spoil – Material removed to expose ore.  Tailings – Mineral processing wastes.  Both have large adverse environmental impacts.  Acid leachates contaminate ground and surface water.  Aesthetic disruption.  Respirable dusts.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources
  • 43. This concludes the Chapter 15 Riches in Rock: Mineral Resources LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 15: Riches in Rock: Mineral Resources