APES Unit 5.9 Impacts of Mining

Practice FRQ (3 sentences minimum)

★ An abandoned coal mine site has been found to have very high sulfur levels in the tailings and overburden left at the site.

Describe one environmental impact of the high sulfur content of the overburden and tailings. Propose a solution to remedy or reduce this impact.

High sulfur levels in tailings and overburden at a coal mine site has negative effects on water conservation. Toxic chemicals can infiltrate deeper into the soil and deposit into fresh groundwater, contaminating the organisms and bacteria that live in the soil or human/animal drinking water. A solution to overburden and tailings can be to pass legislation requiring miners to clear the site of waste.

Crustal Abundance

Average concentration of an element in Earth’s crust

• 88%

  • O2

  • Si

  • Al

  • Fe

Main Types of Mining Techniques

1. Surface Mining

2. Subsurface Mining

Ores

Concentrated accumulations of minerals from which economically valuable materials can be extracted

• Most Accessible Ores: Mined first

• Lower Concentration + Access: Takes more NRG

  • → Disturbances: Pollution, Waste, Soil, Erosion

Metals

Are elements with properties that allow them to conduct electricity and heat energy and to perform other important functions

• Common: Cu, Ni, Al

• Uncommon: Neodymium, Li, Lanthanum

  • Hybrid electric vehicles, photovoltaic solar cells. batteries

Reserve

in resource management, the known quantity of a resource that can be

economically recovered

• Publicly Known Estimate

Overburden

Soil, vegetation, & rocks that are removed to get to an ore deposit

below

Tailings and Slag

Leftover waste material separated from the valuable metal or

mineral within ore (often stored in ponds at mine site)

Surface Mining

Removal of overburden to access ore near surface

• Removal: Vegetation, topsoil, soil

  • → erosion, habitat loss

• Types: Open pit, Strip, Mountaintop Removal, Placer

Subsurface Mining

As ore near surface becomes scarcer, mining moves deeper underground to subsurface mining (more dangerous & expensive)

• High Cost for Workers: Insurance, Healthcare

• Vertical Shaft: Drilled down into grown

  • Elevator: Often for coal—carries resources and workers

• Increasingly Used: as Surface coal deposits depleted

Surface Mining Techniques

1. Strip Mining

2. Open-Pit Mining

Strip Mining

Removal of overlaying vegetation and “strips” of soil and rock, called

overburden, to expose the underlying ore

• Use: When ore is close to earth's surface

  • → Erosion

  • → Mine Tailings

Open-Pit Mining

Creates a visible pit or hole close to the surface but extends beneath the surface both horizontally and vertically

• ex. Copper Mines

Mountaintop Removal

Miners remove the entire top of a mountain with explosives

• Large earth-moving equipment: Removes resources + deposits +

tailings in lower revelation regions nearby

Placer Mining

The process of looking for minerals, metals, and precious stones in river sediments

• River Water: Used to separate heavy items from lighter items

  • ex. Gold, diamonds, tantalum

Environmental Impacts of Mining

1. Rainwater: moves sulfuric acid into streams or ground water

• → Lowers pH of water: toxic metals (Hg + Al) more soluble in water sources

2. Methane Release: CH4 from rock around coal

• → Vented out of mine to prevent explosion: seeps out after mine closes

3. Almost always requires the construction of roads or

railroad beds

• → soil erosion

• → damage to waterways

• → habitat fragmentation

4. Acid Mine Drainage: Rainwater leaks into abandoned mined tunnels → mixes with pyrite → sulfuric acid

Human Safety

1. Accidents: Burial, explosions, fires

2. Inhalation: Gas, dust, particles for long time → upper respiratory diseases

3. Methane Release: Potential for explosions + suffocation b/c lacks oxygen