Expert Report

Each report is produced by a committee of experts selected by the Academy to address a particular statement of task and is subject to a rigorous, independent peer review; while the reports represent views of the committee, they also are endorsed by the Academy. Learn more on our expert consensus reports.

Key Messages

  • A similar analysis of the waste use and disposal technologies that make up the coal system would have value.
  • Although the committee has not identified any deficiencies, it is a matter of due diligence that MSHA and OSM and industry employ the best available current technology.
  • Although there are alternatives to disposing of coal waste in impoundments, no specific alternative can be recommended in all cases. Acceptable alternatives are highly dependent upon regional and site specific conditions. Also, the alternatives that have been identified are in varying stages of technological development and implementation.
  • As advances are made in the use of low value coal or coal water slurry, remining of slurry impoundments can be an attractive source for fuel supply.
  • Geophysical techniques can be useful in coal mine void detection, especially the use of seismic surface waves, seismic reflection, ground-penetrating radar, and electrical resistivity methods.
  • Geophysical techniques have been underutilized in the coal-mining industry and could benefit from additional research.
  • Selecting the appropriate mitigative measures relies strongly on reliable basin characterization.
  • Technologies for utilization of fine coal waste for electricity generation in conventional coal-fired power plants are available. These technologies offer near-term opportunities for the reduction of fine coal waste disposed of in impoundments.
  • The design process for impoundments would be improved by a more formal risk analysis. Proposed new impoundments should also be assigned to risk categories, based on a combination of hazards and consequences, as was suggested for existing impoundments.
  • There are opportunities for additional continuous monitoring that may offer timely warning in case of impending failure of an embankment or basin.
  • Timely review is an essential component of an effective regulatory process. An efficient and coordinated regulatory review process can be of substantial benefit to both the applicant and the jurisdictional agencies.
  • Using different hazard classification methodologies for embankments and basins is inappropriate.
  • While the regulatory review of a proposed impoundment is detailed with respect to the embankment, the regulatory review of the impoundment basin has been less rigorous. The authority for review of the basin characterization and design appears to be covered only in general language authorizing investigation of all relevant issues with respect to the impoundment.
  • Atmospheric fluidized-bed units are already in use for combustion of fine coal waste slurries from both preparation plants and old slurry impoundments, but they have not gained wide usage.