Coal Mining

A front loader piles coal at a coal-fired power station in New York.

David Parsons

Surface mining and deep underground mining are the two basic methods of coal extraction. Many coals also require washing in a coal preparation plant. The most economical mining method depends on the depth of the coal, its quality and thickness, and the density of the overburden (material above the coal seam). Geology and environmental factors are also important considerations. Mountaintop coal mining is a type of surface mining that removes mountaintops to expose coal seams and discards the overburden in adjacent "valley fills." Valley fills occur in steep terrain where there are limited disposal alternatives. Abandoned mine lands are degraded lands and waters that are inadequately reclaimed after surface coal mining operations. These often occur in areas that were not subject to the reclamation requirements of the Surface Mine and Reclamation Act (1977, P.L. 95-87).

Fish and Wildlife Considerations

Trees and vegetation may be removed from the area to be mined for coal. Roads are constructed to provide access for trucks and heavy equipment. Blasting, excavation and placing excess material into valley fills or other locations may further degrade habitats. Stream crossings, stream relocation or even complete stream burial may occur. Soil placed in streams may contain contaminants or other materials that can change the water chemistry, such as acidity and conductivity. Some forest dwelling migratory birds (e.g., Cerulean warblers), migratory tree bats and other animals may be disturbed or even killed during forest clearing activities. Wildlife may also be displaced from the area due to habitat fragmentation and human activities.

Aquatic species and animals that live near streams may be harmed or killed when material is placed in streams. Changes in water quality and quantity may result in changes in the number and types of species living in and around the stream. Invertebrates and salamanders are especially sensitive to changes in water flow and chemistry. Current research indicates that it is very difficult to fully restore a stream after completing mining activities. The inability to completely restore streams after placing fill material can result in permanent loss of stream function and value. It is best to avoid high quality streams in favor of previously impacted streams whenever possible.

Environmental problems associated with abandoned mine lands include surface and ground water pollution, open mine entrances and water-filled pits. Mine sites and refuse piles may be unreclaimed or inadequately reclaimed, including some with dangerous highwalls that can be several stories tall. Other problems include sediment-clogged streams and damage from landslides. Fumes and surface instability may result from mine fires and burning of coal refuse. Environmental restoration activities under the abandoned mine reclamation program are designed to correct or mitigate these problems.