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)
Building Materials: what did students do with their 9000 pounds of sand and gravel last year? That’s the per capita annual production in the US. Many cities are facing shortages of building materials, not because the materials are rare, but because residents object to having quarries and gravel pits nearby.
The building stone industry in the US was almost extinct. Then stone became fashionable and within a few years in the 1980’s production of granite and marble increased tenfold.
Ferrous Metals: recycled iron and steel now amounts to more dollar amount than mined iron.
Gold and Silver: in 1965, the value of silver for photography climbed to the point where there was more than 25 cents worth of silver in a quarter. Even the Federal Government is smart enough to figure out that was a losing proposition, and stopped minting silver coins in During World War II, copper was in such demand for artillery shell casings that we minted steel pennies in To save on copper, wires at the Oak Ridge atomic facility were made of silver from the Treasury – it worked because the facility was under such tight security. By 1944 the copper shortage had eased and recycled shell casings were used to mint pennies. Collectors call 1944 and 1945 pennies “shell case” cents.
Platinum is worth as much as gold, but is in such demand as a catalyst and for chemical uses that its value fluctuates wildly, so it is not used in coins very much.

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 Subsurface (underground) Placer – dredging (Au)
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 Economic Impact Environmental Problems
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!