5.9 Impacts of Mining

Extracting resources from the Earth

Mining removes minerals and fossil fuels from the ground. Strip mining and open-pit mining scrape away surface layers, destroying habitats and topsoil. Subsurface mining tunnels underground, causing less surface disturbance but risking cave-ins and worker exposure to hazards like coal dust and methane.

Chemical and water impacts

Acid mine drainage occurs when sulfur compounds exposed by mining react with water and air to form sulfuric acid, which leaches toxic heavy metals into waterways, killing aquatic life. Mountaintop removal buries streams with debris (valley fill), while processes like heap-leach mining use cyanide or mercury, risking spills and groundwater contamination.

Restoring mined land

Reclamation is the process of restoring mined land to a usable, stable condition — regrading slopes, replacing topsoil, and replanting vegetation. Laws like the U.S. Surface Mining Control and Reclamation Act (SMCRA) require reclamation, but full ecosystem recovery is slow, and some damage (like AMD) can persist for decades.

Key terms

Strip/open-pit mining

Surface mining methods that remove soil and rock layers to access minerals, causing major habitat and topsoil destruction.

Subsurface mining

Underground mining that limits surface damage but increases risks like cave-ins and exposure to toxic gases.

Acid mine drainage (AMD)

Sulfuric acid formed when sulfide minerals react with water and air, leaching toxic heavy metals into waterways.

Mountaintop removal / valley fill

Mining method that removes mountain peaks; debris (valley fill) buries streams and disrupts watersheds.

Reclamation

Restoring mined land by regrading, replacing topsoil, and replanting vegetation, often required by law (e.g., SMCRA).

Try an AP-style question

What is acid mine drainage?

1. Water pumped into mines
2. Mining that uses acid on purpose
3. Natural acid rain
4. Acidic runoff from exposed mine rock