1. Minerals and the Environment

2. 2. Domestic and foreign companies take out $2-$3 billion/ year
I. Mining Law of 1872 – encouraged mineral exploration and mining.
1. First declare your belief that mineral deposits are on the land. Then spend $500 in improvements, pay $100 per year and the land is yours
2. Domestic and foreign companies take out $2-$3 billion/ year
3. Allows corporations and individuals to claim ownership of U.S. public lands.
4. Leads to exploitation of land and mineral resources. 2

3. -- Senator Dale Bumpers (D- AR, retired)
"This archaic, 132-year-old law permits mining companies to gouge billions of dollars worth of minerals from public lands, without paying one red cent to the real owners, the American people.  And, these same companies often leave the unsuspecting taxpayers with the bill for the billions of dollars required to clean up the environmental mess left behind."
-- Senator Dale Bumpers (D- AR, retired) 3

4. Nature and Formation of Mineral Resources
A. Ore – a concentration of naturally occurring material in or on the earth’s crust that can be extracted and processed at an affordable cost. Mineral and energy resources such as coal, oil, gold, and copper are nonrenewable resources. 4

5. Nature and Formation of Mineral Resources
1. Metallic Mineral Resources – iron, copper, aluminum
2. Nonmetallic Mineral Resources – salt, gypsum, clay, sand, phosphates, water and soil.
3. Energy resource: coal, oil, natural gas and uranium 5

6. Ore Formation
1. Magmatic Concentration – magma cools and crystallizes into various layers with denser Fe and Mg containing magma sinking while lighter Si containing magma forming upper layers 6

7. Ore Formation
Hydrothermal Processes: most common way of mineral formation
A. Gaps in sea floor are formed by movement of tectonic plates
B. Water enters gaps and comes in contact with magma
C. Superheated water dissolves minerals from rock or magma
D. Metal bearing solutions cool to form hydrothermal ore deposits.
E. Black Smokers – upwelling magma solidifies. Miniature volcanoes shoot hot, black, mineral rich water through vents of solidified magma on the seafloor. Support chemosynthetic organisms. 7

8. Ore Formation
Manganese Nodules (pacific ocean)– ore nodules crystallized from hot solutions arising from volcanic activity. Contain manganese, iron copper and nickel. 8

9. Methods For Finding Mineral Deposits
A. Photos and Satellite Images
B. Airplanes fly with radiation equipment and magnetometers
C. Gravimeter (measures local difference in gravitational forces)
D. Drilling
E. Electric Resistance (measure resistance of the Earth to the passage of an electric current)
F. Seismic Surveys
G. Chemical analysis of water and plants 9

10. Methods of Mining Surface mining open-pit mining dredging
copper, iron, sand, gravel, limestone
dredging
buckets and draglines scrape underwater deposits
In surface mining, mechanized equipment strips away the overburden of soil and rock and usually discards it as waste material called spoils.

11. Methods of Mining Surface mining open-pit mining dredging
copper, iron, sand, gravel, limestone
dredging
buckets and draglines scrape underwater deposits
In surface mining, mechanized equipment strips away the overburden of soil and rock and usually discards it as waste material called spoils.

13. Strip mining overburden (and all vegetation) is removed in strips
resource is removed
spoil is replaced in rows
spoil is susceptible to erosion (sediment pollution)
rainwater leaches chemicals into ground water (acid drainage)
Area strip mining: used where the terrain is fairly flat
Contour strip mining: used on hilly or mountainous terrain

14. Mine tailings Mine tailings often include sulfide compounds
When these react with water, sulfuric acid and toxic minerals can be washed into local water
Ore has two components
Ore mineral containing the desired metal
Gangue the waste material
Removing the gangue from the ores produces piles of waste called tailings.

15. Subsurface mining coal mining disturbs less than 1/10 as much land
produces less waste
more dangerous to miners than surface mining

16. Heap-leach Extraction
heap-leach extraction - separating gold from low grade ores - spraying rock with a cyanide solution which dissolves the gold - mining sites are often left with high toxin levels
Cyanide, a highly toxic chemical, is used to separate 85% of the world’s gold from waste ore.

17. Placer Mining
placer mining – mining streambed deposits for gold and other minerals
Destroys riverbanks and vegetation along banks
Increases sediment in rivers
Uses heavy metals like Mercury that contaminate waters
in the Amazon, gold miners are using mercury and have dumped 100 tons of mercury into the Amazon river

18. Minerals are extracted from ores by heating or chemical reactions
Smelting - heating the ore - produces huge amount of air pollution (SOx)
In the US, the mining industry produces more toxic emissions than any other industry
After gangue has been removed, smelting is used to separate the metal from the other elements in the ore mineral.
In the U.S., the mining industry produces more toxic emissions than any other industry.

19. Environmental Effects
Steps
Environmental Effects
Disturbed land; mining accidents;
health hazards; mine waste dumping;
oil spills and blowouts; noise;
ugliness; heat
Mining
exploration, extraction
Processing
Solid wastes; radioactive material;
air, water, and soil pollution;
noise; safety and health
hazards; ugliness; heat
transportation, purification,
manufacturing
Use
Noise; ugliness
thermal water pollution;
pollution of air, water, and soil;
solid and radioactive wastes;
safety and health hazards; heat
transportation or transmission
to individual user,
eventual use, and discarding
Fig. 14.6, p. 326

20. Percolation to groundwater Leaching of toxic metals
Subsurface
Mine Opening
Surface Mine
Runoff of
sediment
Acid drainage from
reaction of mineral
or ore with water
Spoil banks
Percolation to groundwater
Leaching of toxic metals
and other compounds
from mine spoil
Leaching may carry
acids into soil and
ground
water supplies
Fig. 14.7, p. 326

21. Scattered in environment
Smelting
Separation
of ore from
gangue
Melting
metal
Conversion
to product
Metal ore
Recycling
Surface
mining
Discarding
of product
Fig. 14.8, p. 327
Scattered in environment

22. A. Life Cycle of Metal Resources
Mining Ore
A. Ore has two components: gangue (waste) and desired metal
B. Separation of ore and gangue which leaves tailings
C. Smelting (air and water pollution and hazardous waste which contaminates the soil around the smelter for decades)
D. Melting Metal
E. Conversion to product
F. Discarding of product 22

23. Recycle; increase reserves by improved mining
Mine, use, throw away;
no new discoveries;
rising prices
Recycle; increase reserves
by improved mining
technology, higher prices,
and new discoveries B
Production
Recycle, reuse, reduce
consumption; increase
reserves by improved
mining technology,
higher prices, and
new discoveries C
Present
Depletion
time A
Depletion
time B
Depletion
time C
Fig. 14.9, p. 329
Time