THE ENVIRONMENTAL IMPACTS OF MINING, PROCESSING, AND USING COAL

Our country has large coal reserves and growing energy needs. Currently, coal accounts for 30 percent of our Nation's total energy and 50 percent of its electricity. Even if the use of other fuels substantially increases in the future, coal will continue to be important source of energy. Hence, it is important to understand the environmental impacts of mining, processing, and utilization of coal. Many impacts are legacy issues, which is an important distinction because modern mining, processing, and utilization are strictly regulated. Pre-law mining issues include physical disturbances; increased sedimentation; subsidence; landslides; water quality; mine fires; and safety issues such as abandoned highwalls, impoundments, and equipment. These impacts vary depending on the seam mined, the location (topography, climate), hydrology, and mining method used. Most are concentrated in basins and states with long mining histories. Likewise, modern issues such as the controversies surrounding mountaintop mining are not universal and tend to be at least coalfield- or basin-specific.

Similarly, the environmental impacts of coal preparation are concentrated in specific parts of the United States, because coal processing is concentrated where higher-sulfur coals are mined. Environmental issues related to coal processing include water quality issues such as acidic drainage, slurry impoundment discharges, physical disturbances, and gob fires.

The environmental impacts of coal use, mostly for electric power, include harmful emissions and solid waste disposal. Emissions of concern include sulfur and nitrogen oxides that lead to acid rain; particulate matter that causes haze; mercury and its health impacts; and carbon dioxide and its potential to change climate. The latter is currently unregulated, but much effort is being spent on finding methods for decreasing carbon dioxide emissions, including geologic sequestration. Utilization impacts vary with the chemistry and quality of the coal used, type of power generation and environmental technology used at individual plants, hydrology, and climate.

Scientific understanding of the causes and methods for mitigating past impacts and preventing future impacts is essential to our use of coal as a fuel. Geologists have an important role to play in this understanding.