Which mining practice involves removing mountaintops and placing debris in adjacent valleys?

• A. Subsurface mining
• B. Open-pit mining
• C. Mountaintop mining
• D. Offshore mining

Answer: (C)

Mountaintop removal mining is the practice described. It’s a surface mining method used mainly to access coal seams near the top of mountains. The summit and much of the overlying rock are blasted away, and the resulting waste rock is pushed into adjacent valleys, often burying streams and altering the watershed. This distinguishes it from subsurface mining, which tunnels underground to reach minerals, and from open-pit mining, which digs a large pit in flatter terrain rather than removing an entire mountain and dumping the waste into nearby valleys. Offshore mining occurs on the ocean floor. The environmental stakes are high because the waste placement fills in valleys, silts streams, destroys habitats, and can lead to degraded water quality from sedimentation and acid mine drainage—issues central to Clean Water Act considerations and regulated reclamation efforts.