Introduction - Coal Waste Impoundments: Risks, Responses, and Alternatives - page 16

the proximity of underground workings; to determine whether the
recommendations of Bureau of Mines Information Circular 8741 (Babcock and
Hooker, 1977), which provides guidelines for mining under bodies of water, are
met; and to assess the potential impact if a breakthrough were to occur. For
example, the impact may threaten the safety of miners or the safety of the
general public (MSHA, 1997). A priority rating is assigned to each
impoundment based on its breakthrough potential — whether low, medium, or
high—and a potential impact of a breakthrough. The purpose of this
classification system is to evaluate whether the impoundment plan adequately
addresses the breakthrough potential (MSHA, 1997). These ranking systems are
based on the proximity of the basin to underground workings as well as the
potential downstream impacts were a basin to fail. However, they do not assess
the probability of failure. It is a completely separate ranking than that which is
done for the embankment structure.
In addition, the Federal Emergency Management Agency ranks
embankments based on potential impacts should a failure occur (U.S. Bureau of
Reclamation, 1988). This inventory lists more than 76,000 dams. The Office of
Surface Mines (OSM) and the state delegate programs use a similar system to
rank earth dams and reservoirs by whether they are located in rural areas and
the amount of damage failure could cause (U.S. Department of Agriculture,
1976). Neither of these organizations has a ranking system for breakthrough
potential.
STUDY AND REPORT
Concern about the potential for accidents like the one at Inez, Kentucky
(October 2000), motivated Congress to direct MSHA to commission an
independent study of current coal waste disposal methods and an exploration of
alternatives for future disposal of coal waste. In addition, Congress directed that
the study examine engineering standards for coal waste impoundments, and
recommend ways to improve the stabilization of impoundment structures.
The National Research Council (NRC) established the Committee on Coal
Waste Impoundments to undertake this study. The committee consists of 14
experts from academia, industry, and state government with expertise in coal
mining, geology, geophysics, geochemistry, hydrology, mining regulations,
environmental law, mining health and safety, land-use planning, and
geotechnical and geological engineering. Brief biographies of the committee
members appear in Appendix A .