1. Mining

2. From the topic outline IV. Land and Water Use
Mining (Mineral formation; extraction; global reserves; relevant laws and treaties)

3. 14.3 What Are Mineral Resources and What Are The Environmental Effects of Using Them?
Some naturally occurring materials in the Earth’s crust can be extracted and made into useful products in processes that provide economic benefits and jobs.
Extracting and using mineral resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil.

4. Bellwork
If your group had been able to secure site 16 for mining of Molybdenum, what would be your next step? What type of mine would you most likely have? To whom would you sell the molybdenum? (Hint: use your device to research possible answers!)
What is reclamation?

5. Minerals
Mineral Resource: Naturally occurring, inorganic, material from crust
Ore: Rock that contains a large concentration of a mineral
High Grade Ore: Large amount of mineral
Low Grade Ore: Smaller amount of mineral

6. Ore Examples If you can’t grow it, you have to MINE it! Element Ore
Silicon
Quartz
Aluminum
Bauxite
Iron
Magnetite or Hematite
Calcium
Gypsum or Calcite
Sodium
Halite
Magnesium
Magnesite or Dolomite
Potassium
Sylvite
Copper
Chalcopyrite
Tin
Cassiterite
Lead
Galena
Zinc
Sphalerite

7. Cookie Mining Mining for chocolate ore You control your profits
Choose your “land” (cookie)
Choose your tool(s)
Determine how best to mine and how achievable reclamation will be
You will be charges for any land that is not reclaimed

8. Important Minerals and their Uses

9. Estimating Mineral Resources
Key terms used by USGS:
Identified: location, quantity, and quality known based on direct measurements.
Undiscovered: potential supplies assumed to exist.
Reserves: identified resources that can be extracted profitably.

10. Effects of Mineral Use
No matter the mineral, all steps use large amounts of energy and creates pollution.
High grade = less energy needed
Low grade = more energy needed

13. Environmental Effects
environmental effects, cont.
toxic chemicals can also be emitted to the atmosphere
metal ores are extracted, purified, smelted, and made into desired products
ore consists of ore mineral and gangue
ore is separated from gangue, smelted to obtain the metal, and made into products that are used and discarded or recycled
there can be enormous amounts of air and water pollution from these processes

14. Harmful Effects

15. Environmental Effects
mining, processing, and use of mineral resources uses large amounts of energy, causes land disturbance, and air and water pollution
land is scarred and the surface is disrupted; cleanup may cost billions
subsidence from underground mining can cause pipelines to break
mining wastes contain toxins, and acid drainage contaminates streams and groundwater

16. Fig 16-14 Pollution of water from mining

17. Environmental Effects
environmental effects, cont.
toxic chemicals can also be emitted to the atmosphere
metal ores are extracted, purified, smelted, and made into desired products
ore consists of ore mineral and gangue
ore is separated from gangue, smelted to obtain the metal, and made into products that are used and discarded or recycled
there can be enormous amounts of air and water pollution from these processes

18. Environmental Effects
Disturbs large area
Prone to erosion
Uses large quantities of water
Must pump water out of mine to keep it dry
Acid Mine Drainage (AMD)
Pollution caused when sulfuric acid and dissolved lead, arsenic or cadmium wash out of mines into nearby waterways

19. Environmental Effects of Gold Mining
Gold producers
South Africa
Australia
United States
Canada
Cyanide heap leaching
Extremely toxic to birds and mammals
2000: Collapse of a dam retaining a cyanide leach pond
Black Hills : S. Dakota

20. Acid Mine Drainage

21. Finding, Removing, Processing
promising underground deposits of minerals are located by a variety of physical and chemical methods
methods include aerial photographs, satellite images, radiation-measuring equipment, magnetometer, gravimeter
underground methods are also used such as seismic surveys, analyzing shock waves from explosive charges, and use of chemical analysis of water and plants for leached materials

22. Extracting Minerals from Deposits
Surface Mining
Remove overburden (discarded as spoils) to get to mineral deposits
Types
Open-Pit
Strip
Contour Strip
Dredging
Mountain-Top Removal

24. Open Pit Mining Machines dig large holes in ground, remove ores
Toxic water can collect at bottom of pit

25. Strip Mining
Similar to open-pit, but only useful when deposits are horizontal and near surface

26. Specific kinds of surface mining
Open-pit mining
Strip mining
Holes are dug
Ores are removed
Iron, copper, gold, sand, gravel, stone
Used for horizontal beds of minerals
Area strip mining: flat land
Contour strip mining: hills
Coal (70%)

27. Contour Strip Mining Used in hilly or mountain areas Cut terraces
Remove overburden and use to make new terrace

28. Dredging
scrapes up underwater mineral deposits

29. Mountain-Top Removal
Literally remove the top of mountains (!!!)

30. Surface mining method: mountain-top removal
Mountain top removed
Exposes deposits
Prominent in Appalachian mountains
Ex. Coal

31. Mountain-Top Removal Example

32. Eureka! Gold Mining Placer Deposits (gravity separation)
Panning
Sluicing
Dredging
Hard Rock Deposits
Open pit
Hydraulic mining (sometimes with Hg)
Subsurface - S. Africa 12, 800 feet underground
Cyanide is used to extract gold
In comparison - Mt Baldy is ft

33. Removing Metals from Ores
Negative consequences:
Scarring/disruption of land surface
Large amount of spoils
Large amounts of solid waste
Toxic or acidification of water (H2SO4, etc.)
Gangue (“gang”)
Air pollution

34. 14.4 How Long Will Supplies of Nonrenewable Mineral Resources Last?
All nonrenewable mineral resources exist in finite amounts, and as we get closer to depleting any mineral resource, the environmental impacts of extracting it generally become more harmful.
An increase in the price of a scarce mineral resource can lead to increased supplies and more efficient use of the mineral, but there are limits to this effect.

35. Depletion of Resources
Future supply depends on two factors:
Actual supply
Rate of use
Depletion time
Use up 80% of resource
After depletion:
Recycle, waste less, use less, find a substitute, do without

36. Economic Depletion
As known resources are depleted, it becomes more expensive and difficult to get to new supplies
We might still have resources left, but it will be TOO COSTLY to utilize them on a wide-scale

37. U.S. General Mining Law of 1872
To encourage mining of “hard rock” minerals
How it works:
File claim that you believe land contains valuable minerals
Promise to spend $500 to improve it
Purchase public land for $2.50 to $5.00 an acre (!!!)
Pay $120 a year for each 20-acre parcel of land
Law frozen in 1995 – by that time, estimated $285 billion of public land “given away” at 1872 prices
Since clean up requirements only came in 1992, there are an estimated 500,000 sites that will cost taxpayers $32-72 billion to clean up!

38. Example of 1872 Law “Give Away”
In 2004, a mining company purchased 155 acres of public land near Crested Butte for $875
Land could be worth $155 million
Each year, companies remove $4 billion worth of minerals each year and only pay 2.3% of the value in tax (compared to 13.2% for oil or 14% for grazing rights)

39. 14.5 How Can We Use Mineral Resources More Sustainably?
We can try to find substitutes for scarce resources, reduce resource waste, and recycle and reuse minerals.

40. Reclamation The good news: Mining now requires reclamation
Reclamation: Returning the land as close as possible to original state.

41. Copper Basin, TN

42. Surface Mining Control and Reclamation Act of 1977
requires mining companies to restore most surface-mined land
reclamation efforts are only partially successful
subsurface mining removes coal and various metal ores too deep for surface mining
subsurface mining disturbs less than 1/10 as much land as surface mining with less waste, but is more dangerous and expensive

43. Restoration of Mining Land
Creative Approaches
Wetlands
Trap and filter pollutants before they get into streams
Initially expensive, but cost effective compared to using lime to decrease acidity
Phytoremediation
Use of specific plants to absorb and accumulate toxic materials in soil

44. Industrial Ecosystems
Design industrial process to mimic nature

45. Uneven distribution of minerals
Most of the nonrenewable mineral resources supplied by
Canada
United States
Germany
Russia
South Africa: self sufficient in all key minerals, largest producer of gold, chromium and platinum
Australia
8% of world population, consume 75% of the world’s key metals
China increasing consumption

46. Minerals in Antarctica
No substantial mineral deposits identified to date
Antarctica Treaty (1961)
Limits activity to peaceful uses (i.e., scientific studies)
Madrid Protocol (1990)
Moratorium on mineral exploration and development for minimum of 50 years

47. Finding Mineral Substitutes
Important goal in manufacturing
Substitute expensive/scarce mineral resources for inexpensive/abundant ones
Examples:
Using plastic, glass or aluminum in place of tin
Using glass fibers instead of copper wiring in telephone cables

48. Mineral Conservation
Includes reuse and recycling of existing mineral supplies
Reuse - using items over and over again
Reduces both mineral consumption and pollution
Recycling - converting item into new product
Reduces land destruction from mining
Reduces solid waste