Mineral Formation & Extraction Ch. 14

We can make some minerals in the earth’s crust into useful products, but extracting and using these resources can disturb the land, erode soils, produce large amounts of solid waste, and pollute the air, water, and soil.

How are minerals used?

Mineral Element/compound of elements naturally occurring in the crust EX. Steel = Iron & Carbon Bronze = Tin & Copper Copper Sulfur

Where are minerals found? Rocks – combinations of minerals Ore/ore body – concentrated mineral chunk that can be mined for profit

Ore/Ore Body High Grade Large amounts of particular mineral Low Grade Small Amounts of minerals

Classification of Minerals Mineral resources include: –Metallic –Non-metallic –Energy Resources Non-renewable

Classification Metallic Iron, Copper, Aluminum – Malleable – Lustrous – conductors Nonmetallic Sand Stone Phosphates Salts

Classification Energy Resources –Coal –Oil –Natural Gas –Uranium

How do minerals form?

Magma Black smoker Sulfide deposit White crab Tube worms White smoker Hydrothermal ore also occur when upwelling magma solidifies into black smokers Especially rich in Cu, Pb, Zn, Ag, Au

How do minerals form?

How are minerals discovered and extracted? 1.Prospecting 2.Mining/Extractions 3.Smelting/Processing

1. Prospecting Finding places where ores occur. Is it profitable to mine? $$$$

Prospecting Tools Satellite Imagery Aerial Sensors (magnetometers) Gravity Difference (gravimeter) Core Sampling Seismic Surveys Chemical analysis of water & plants

2. Mining Extracting Surface Less $ Open Pit Strip Mining Safer for miners Environmental Damage Subsurface More $$$ Shaft Slope Hazardous for miners Less Environmental Damage

Surface Mining Mechanized equipment strips overburden of soil & rock Discards it as waste called spoils In US: –90% of nonfuel mineral & rock resources –60% of coal by weight

Surface Mining Types Open-pit mining

Surface Mining Types

Surface Mining Types * Area Strip Mining

Surface Mining Types

Contour Strip Mining

Undisturbed land Overburden Pit Bench Spoil banks

Surface Mining Types Mountaintop Removal

Mountaintop Coal Mining in West Virginia Fig , p. 359

Ecological Restoration of a Mining Site in Indonesia Fig , p. 360

Subsurface Mining Used to remove coal and various metal ores that are too deep to be extracted by surface mining

Subsurface Mining Shaft Slope –Disturbs less land –Produces less waste –More dangerous –More expensive

3. Smelting/Processing * Heat to extract pure ore from impurities

Surface mining Metal oreSeparation of ore from gangue Smelting Melting metal Conversion to product Discarding of product Recycling Life Cycle of a Metal Resource

Environmental Implications Remember: Mining is an economical activity.

Environmental Implications Decisions to mine depend on: -Financial risk -Potential profit -Risk of environmental damage -Economic viability of mineral NOT A SIMPLE ISSUE!

Natural Capital Degradation Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources StepsEnvironmental Effects MiningDisturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Exploration, extraction ProcessingSolid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Transportation, purification, manufacturing UseNoise; 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

Environmental Implications

Environmental Effects of Extracting (Mining) and Processing Fig p. 344

Land damage of surface and vegetationLand damage of surface and vegetation Water use threatens supplies of groundwaterWater use threatens supplies of groundwater Water quality damage: heavy metals are leached resulting in acid mine drainageWater quality damage: heavy metals are leached resulting in acid mine drainage Gangue: worthless material that surrounds, or is mixed with minerals in an ore deposit.Gangue: worthless material that surrounds, or is mixed with minerals in an ore deposit. Environmental Effects of Mining/Extraction

Tailings: mine waste from impurities in ore can be toxicTailings: mine waste from impurities in ore can be toxic Air pollution from smelting plantsAir pollution from smelting plants Energy requirements of equipment, processing, refining, labor intensive, etc.Energy requirements of equipment, processing, refining, labor intensive, etc. Subsidence or collapseSubsidence or collapse

Environmental Effects of Using a Mineral Resource a)Disruption of land surface 500,000 mines b)Subsidence c)Erosion of solid mining waste d)Acid mine drainage H 2 SO 4 e)Air pollution Mining produces more toxic emissions than any other industry f)Storage and leakage of liquid mining waste

Legislation Surface Mining Control and Reclamation Act of 1977 –Requires mining companies to restore most surface-mined land so it can be used for the same purpose as it was before it was mined –Levied a tax on mining companies to restore land that was disturbed by surface mining before the law was passed.

Legislation General Mining Act of 1872 –allowed individuals/corporations to stake claims to mine metals on federal lands at $2.50 to $5 per acre –cheap land for developing the western US by patenting –law contains no provision for env. protection or reclamation of topsoil/vegetation/habitat

Fun Facts EX. In 1995  ASARCA (US company) paid $1,745 for land that produced $2.9 billion worth of minerals (Cu/Ag) EX  Manville Corp. paid $10,000 for land in Montana that contains about $32 billion of palladium and platinum Of the ~1200 Superfund sites (the nations worst toxic waste sites) about 52 are mines.