1. Mining What is it? Why do we do it? What does it do to the Earth?
How can we be more sustainable?

2. …Minerals Mineral Groups: Can be:
NATURALLY OCCURRING
INORGANIC
SPECIFIC CHEM. COMP.
SOLID
DEF. CRYSTAL STRUCTURE
Mineral Groups:
Sulfides (S + another element)
Oxides (O + metals)
Halides (F, Cl, Br, I)
Silicates (Si + O)
Carbonates (C + O)
Native Elements (any pure element)
Can be:
Metallic
Nonmetallic
Rocks = combo of minerals + other stuff
Ore = rock that contains a large enough concentration of a mineral that makes it profitable to mine for.
High-grade ore: large amounts of minerals
Low-grade ore: low amounts of minerals.

3. Mineral Resources Naturally occurring in earth’s crust
Must be extracted, processed
Examples
Energy (oil, coal, natural gas, uranium)
Metallic minerals (aluminum, iron, copper, gold)
Nonmetallic minerals -
Aggregate: sand, gravel
Fertilizers: potash, phosphorous
Evaporites: gypsum, halite (salt)
Building Materials: limestone, marble
Nonrenewable!

4. Ores A rock that contains a mineral. Must contain profitable amount
High grade = large amount of desired mineral
Low grade = smaller amount of desired mineral

5. Mineral Resources Magma (Igneous): Sedimentary Processes Weathering
Cooling process causes mineral containing rocks to form
Gold, silver, lead, mercury, copper (found in veins of quartz)
Hydrothermal
Copper, lead, zinc, silver, gold, sulfur
Manganese nodules (sea floor deposits)
Steel processing
Sedimentary Processes
Placer Deposits (river gravels)
gold
Evaporites
Halite, gypsum, borax (soap)
Weathering
Bauxite (aluminum), Fe oxides (pigments)

6. Distribution & Formation
Widely distributed worldwide (see next slide)
Some countries have a lot, some have a little.
===============================================
Magmatic Concentration
Magma cools & separates into layers
Heavy (Fe, Mg) on bottom, Light (SiO2) on top
Hydrothermal Processes
Hot groundwater dissolves minerals & react with S, making sulfides
Sulfides aren’t soluble, so they settle out.
Sedimentation
Water transports weathered particles and deposits them as sediment
Evaporation
Salts & minerals are left behind when water evaporates.

7. MAKE THEM INTO A PRODUCT!
How is mining done?
STEP 1:
DISCOVER THEM!
STEP 2:
EXTRACT THEM!
STEP 3:
PROCESS & REFINE THEM!
STEP 4:
MAKE THEM INTO A PRODUCT!

8. Step 1: DISCOVERY Aerial or Satellite photography
Measure Earth’s magnetic field & gravity
Geological knowledge of how minerals form
Drill for samples & analyze composition
Sea floor?? Detailed 3D maps!

9. Step 2: EXTRACTION 2 ways: Surface & Subsurface Mining!
Surface Mining (less $$, less danger)
Overburden must be removed
4 Kinds:
Open-pit mining = dig a big hole to make a quarry.
Strip Mining = dig parallel trenches and create a spoil bank (dump new trench’s overburden in old trench)
Mountaintop Removal = BAD!!!
Dredging = chain buckets & draglines scrape underwater minerals
Subsurface Mining (more $$, more danger)

10. Step 3: PROCESSING Smelting
Melting ore at high temperatures to help separate impurities from the molten metal.
Uses a Blast Furnace
Ore, coke, and limestone react with heat to create:
Purified molten iron (denser)
Iron Ore + Coke = molten iron + carbon dioxide
Impurities (“Slag”) (less dense)
Limestone + Impurities = slag
Exhaust gases are dangerous!

11. … that means… Create a Product!! Duh!
Step 4: CREATE PRODUCT
… that means…
Create a Product!!
Duh!

14. Mineral Resources Identified Reserves Undiscovered
Known location, quantity and quality based on direct evidence
Reserves
Identified resources that can be extracted profitably
Undiscovered
Potential supplies that are assumed to exist

17. How do we use minerals? Gold Aluminum Steel (alloy containing iron)
Electronics, jewelry
Aluminum
Packaging, cars, airplanes
Steel (alloy containing iron)
Buildings, vehicles
Sand
Glass, bricks, concrete
Limestone
Cement, concrete, road rock, building materials

19. The life cycle of a metal resource
Key terms:
Overburden: the soil & rock that lies above the economically important rock.
Gangue: worthless minerals/material that surrounds ore
Smelting: using heat & chemicals to turn ore into useable mineral
Tailings: piles of waste left behind after extraction, contains gangue
Overburden: the soil and rock that lies above the economically important rock.
Gangue: worthless minerals/material that surrounds ore
Smelting: using heat and chemicals to turn ore into useable mineral
Tailings: piles of waste left behind after extraction, contains gangue

20. Mining: the good and the bad
Advantages
Disadvantages
Income!
Revenues for cities, states and countries
Employment
Progress – buildings, cars, electronics
Uses lots of energy
Disturbs land
Erodes soil
Produces a lot of waste
Pollutes air, water, soil

21. Mining Methods Surface mining Subsurface mining
Removal of shallow deposits
Overburden removed
Rock/soil on top of deposit
Discarded as “spoils”
Used in 90% of non-fuel mineral/rock resources
Used in 60% of coal mined in U.S.
Removal of deep deposits
Often used for coal and metal ores
Deep vertical shaft is dug
Tunnels must be blasted
Machinery used to reach deposits

22. Examples of Mining Methods
Surface
Subsurface
Open Pit
Strip
Mountaintop Removal
Placer
Hydraulic
Dredging
Drift
Slope
Shaft
Hard Rock
Borehole
Fracking

25. 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%)

26. Contour Strip Mining Used on hilly or mountainous terrain.
Unless the land is restored, a wall of dirt is left in front of a highly erodible bank called a highwall.
Figure 15-13

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

28. 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

29. Harmful Environmental Effects of Mining
Scarring/disruption of land
Overburden/Spoils left behind, vegetation can’t grow well
H2SO4 – acid runoff
Sediment, erosion, loss of topsoil
Subsidence, cave-ins (sink holes), explosions
Left: December 12, Center: July 27, Right: November 2, Gold mining has been an important industry in California for more than 200 years. The Mesquite Mine, established in 1957, was expanded in 1986 as gold prices climbed and is now one of the largest gold mines in the country. Geologists anticipated that the gold would be exhausted by 1999, but improved extraction methods have kept the mine in production. The Mesquite is in the Mojave Desert, surrounded by a frail ecosystem, so the extraction methods — which use cyanide washes — are carefully monitored. Plans are underway for a major landfill to be installed next to the mine operation, increasing the need to monitor the land-use change

30. Harmful environmental effects of mining
Processing involves many chemicals (sulfuric acid, mercury, cyanide)
Creates toxic waste during processing
Tailings: Often stored in valleys – As, Hg, CN, H2SO4
Can collapse and get into ecosystem
Streams/Groundwater polluted with waste material
Tailings: H2SO4, Hg, CN (Cyanide)
Overburden: Sediment
Overburden: H2SO4 – leaches heavy metals such as As, Cd, Pb, Zn
Air pollution from processing
Highest industrial air polluter of toxic emissions!

32. Harmful effects, cont’d
Forests removed
Loss of Biodiversity
Increased Erosion
Disease (subsurface)
COPD – chronic bronchitis, emphysema
Black lung disease

33. Tailings:

34. How do we fix this? Clean up and restore mining sites
500,000 surface sites in U.S.
$70 billion to clean up
Subsurface disturbs <1/10 the land that surface mining disturbs
Produces less waste
But…causes cave ins, explosions, fires, diseases, deaths

35. 1872 U.S. General Mining Law
Designed to encourage mineral exploration on U.S. public lands and populate the West
Individuals could “claim” land
Must spend $500 to improve land
Could pay $6-12 for land owned by all U.S. citizens
Could build, sell, lease, use it for whatever
Frozen in 1995
Some land still being transferred at 1872 prices!
1992 modification: must post bonds to cover clean up cost in case of bankruptcy
Mining companies trying to weaken

36. General Mining Law (1872) 1872 – do you think it was good or bad??
Encouraged settlement of western states
Anyone can stake a mining claim on federal lands, buy for $ $5 per acre, extract the resources, & keep all profits.
No provisions for environmental protection

37. abandoned mines in the US are Superfund sites!
…General Mining Law (1872)
More than 50
of the 100,000 to 500,000
abandoned mines in the US
are Superfund sites!
Cleanup of all Superfund mining sites
will cost an estimated
$12.5-$17.5 billion.

38. SURFACE MINING CONTROL AND RECLAMATION ACT OF 1977 SMCRA
 Established a program for regulating surface coal mining and reclamation activities
Established mandatory uniform standards for these activities on state and federal lands
requirement that adverse impacts on fish, wildlife and related environmental values be minimized
reclamation of land after mining was completed
Created an Abandoned Mine Reclamation Fund for use in reclaiming and restoring land and water resources adversely affected by coal mining practices.
Standards of Performance. SMCRA and its implementing regulations set environmental standards that mines must follow while operating, and achieve when reclaiming mined land.
Permitting. SMCRA requires that companies obtain permits before conducting surface mining. Permit applications must describe what the premining environmental conditions and land use are, what the proposed mining and reclamation will be, how the mine will meet the SMCRA performance standards, and how the land will be used after reclamation is complete. This information is intended to help the government determine whether to allow the mine and set requirements in the permit that will protect the environment.
Bonding. SMCRA requires that mining companies post a bond sufficient to cover the cost of reclaiming the site. This is meant to ensure that the mining site will be reclaimed even if the company goes out of business or fails to clean up the land for some other reason. The bond is not released until the mining site has been fully reclaimed and the government has (after five years in the East and ten years in the West) found the that the reclamation was successful.
Inspection and Enforcement. SMCRA gives government regulators the authority to inspect mining operations, and to punish companies that violate SMCRA or an equivalent state statute. Inspectors can issue "notices of violation," which require operators to correct problems within a certain amount of time; levy fines; or order that mining cease.
Land Restrictions. SMCRA prohibits surface mining altogether on certain lands, such as in National Parks and wilderness areas. It also allows citizens to challenge proposed surface mining operations on the ground that they will cause too much environmental harm.

39. Increasing our Supplies… Minerals in Antarctica
To date, no substantial mineral deposits have been found in Antarctica.
But we might find some!
FYI – nobody owns Antarctica… so the rules can get sticky when people want to exploit resources.
ANTARCTIC TREATY – 1961
Limits activity in Antarctica to peaceful uses such as scientific studies.
Environmental Protection Protocol to the Antarctic Treaty (Madrid Protocol) – 1990
Moratorium on mineral exploration and development for >50yrs
People are already ruining Antarctica’s fragile ecosystem… science, tourism, noise, pollution…

40. RELEVANT LEGISLATION General Mining Law (1872)
Allowed people to “stake claims” & make profit
Surface Mining Control and Reclamation Act (1977)
Required reclamation of previously mined areas
Only from coal mining!!
Antarctic Treaty (1961)
Limits activity in Antarctica to peaceful uses such as scientific studies
Convention on the Regulation of Antarctic Mineral Resource Activities (1980s)
Never ratified – would have permitted exploitation of Ant. minerals
Environmental Protection Protocol to the Antarctic Treaty (Madrid Protocol) (1990)
Moratorium on mineral exploration & development for >50 years
Designated Antarctica & its marine ecosystem as a “natural reserve dedicated to peace and society”