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Mineral Resources & Mining

Mineral Resources & Mining. Eight chemical elements make up 98.3% of Earth’s crust. Oxygen Silicon Aluminum Iron Calcium Sodium Magnesium Potassium. Other elements comprise 1.7% of Earth’s Crust. Many of these are important to industry

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Mineral Resources & Mining

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  1. Mineral Resources & Mining

  2. Eight chemical elements make up 98.3% of Earth’s crust. • Oxygen • Silicon • Aluminum • Iron • Calcium • Sodium • Magnesium • Potassium

  3. Other elements comprise 1.7% of Earth’s Crust • Many of these are important to industry • Distribution of these elements is not uniform across the Earth. • Examples: • Ni, Ti, Cr, Cu, Pb, Zn, U, Pt, Au, Ag, etc.

  4. Ore • If one or more chemical elements occur in sufficient abundance that they may be mined for a profit, then the rock is termed an ORE.

  5. Classification of Mineral Resources • • Metallic Mineral Resources • Abundant (Iron, Aluminum, Magnesium, Manganese, Titanium) • Scarce (Copper, Lead, Zinc, Chromium, Nickel, Gold, Silver) • • Non-Metallic Mineral Resources • Construction(Sand, Gravel, Clay, Limestone, Gypsum) • Agriculture/Industry(Phosphates, Nitrates, Sodium Chloride, Sulfur) • Ceramics/Abrasives(Feldspar, Clay, Quartz, Diamond, Pumice, Garnet, Corundum)

  6. Processes of ore concentration are related to rock formation. • Rocks are grouped into three major families, based upon their processes of formation. • Igneous Rocks • Sedimentary Rocks • Metamorphic Rocks

  7. Ore formation by igneous processes • Crystal Settling • Dense minerals crystallizing in magma, settle to the bottom of the magma chamber • Ex. – Chromium, Platinum, Nickel, Copper, Lead

  8. Ore formation by igneous processes • Hydrothermal enrichment • water, superheated by magma, dissolves minerals and deposits them in “veins” • Ex. – Copper, Gold, Silver

  9. Ore Formation by Igneous Processes • Lode– many thick mineral veins in a small region • Ex. – The “Mother Lode” during the California gold rush

  10. Hydrothermal Enrichment • Pegmatites– “veins” in rocks • Common form of gold enrichment • Exhalites– Submarine vents of hot, mineral-rich water • “Black Smoker Chimneys” – hydrothermal vents • Associated with mid-ocean ridges

  11. “Black Smokers”

  12. Sulfide Mine in an Exhalite Deposit

  13. Ore Formation by Sedimentary Processes • Placer deposits • Moving water erodes rocks releasing heavy minerals which settle on the bottom of stream beds (ex. – gold) • Ex. - gold

  14. Ore Formation by Sedimentary Processes • Evaporite deposits • Precipitation of salt in shallow marine basins or saline lakes (in arid climates) • Ex. – halite, gypsum, borax

  15. Ore Formation by Metamorphic Processes • During contact metamorphism, pre-existing rock is altered forming ores • Ex. – Lead, Copper, Zinc

  16. Prospecting and Exploration Methods of Discovery: • Satellite and Aerial Photography • Remote Sensing • Geological Mapping • Magnetic Mapping • Gravity Mapping • Radioactivity Mapping • Geochemical Sampling • Electrical Sounding Ground-Penetrating Radar • Seismic Methods • Reflection - Detailed but Expensive • Refraction - Cheap but Not Detailed • Core Sampling and Well Logging

  17. Economic Factors in Mining • Richness of Ore • Quantity of Ore • Cost of Initial Development • Equipment, Excavation, Purchase of Rights • Operating Costs: Wages, Taxes, Maintenance, Utilities, Regulation • Price of the Product • Will Price Go up or down?

  18. Issues in Mineral Exploitation Who Owns (Or Should Own) Minerals? • Landowner • Discoverer • Government Unclaimed Areas: • Sea Floor • Antarctica Who Controls Access for Exploration? • Remote Sensing vs. Privacy

  19. Types of Mines • Surface • Open pit (Au, Cu) • Quarries (stone, gravel, sand) • Strip mines (coal) • Subsurface (underground) • Placer – dredging (Au) • Seafloor– nodules (Mn, Ni, Fe)

  20. Problems with Mining Safety • Mine Wastes/Pollution • Hazardous working conditions • Noise Economic Impact • "Boom and Bust" Cycles Environmental Problems • Exploration • Construction & Operation • Waste Disposal

  21. Reclamation • Returning the land to a more natural state after mining operations have ended Mine Albert, Quebec, before and after reclamation. Government of Quebec

  22. Economic Implications • Ores are not found everywhere • Some ores are richer than others • Ore distribution is a function of geology • Ore distribution is not equal across the world • Some nations are rich in mineral resources • Other nations have few mineral resources • No nation is self sufficient in mineral resources

  23. Environmental Considerations • Mining leaves holes in the ground • Mining adds unusual quantities of sediment to rivers and streams • Mining exposes minerals to interaction with surface and groundwater, which may contaminate them • Mine waste may be unstable - landslides • Smelting may pollute air and water

  24. Why do we need mines?

  25. We all make choices. • Industrialized societies depend on mineral resources • Environmental problems must be considered in extracting wealth from the Earth • Its not Good (environment) vs. Evil (industry) • It’s a compromise, of which, we must make the best!

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