PLACEMENT OF COAL COMBUSTION BY-PRODUCTS AT COAL MINES: AN OVERVIEW OF REGULATORY AND TECHNICAL ISSUES

The beneficial use of Coal Combustion By-Products (CCBs) (i.e. fly ash, bottom ash, flue gas desulphurization material, and fluidized bed combustion material) in coal mines has become an area of intense interest, research, activity, and controversy for decades. Beneficial uses include: (1) a seal to contain acid forming materials and prevent the formation of acid mine drainage; (2) an agricultural supplement to create productive artificial soils on abandoned mine lands where native soils are not available; (3) a flowable fill that seals and stabilizes abandoned underground mines to prevent subsidence and the production of acid mine drainage; (4) a construction material for dams or other earth like materials where such materials are needed as a compact and durable base; and (5) a non-toxic, earthlike fill material for final pits and within the spoil area.

Extensive regulatory authority water quality monitoring data and university research data indicates that the placement of these materials under the permitting and performance standard requirements at a mine regulated under the Surface Mining Control and Reclamation Act (SMCRA) usually results in a beneficial impact to human health and the environment when it is used to mitigate other existing potential mining hazards. In the 30 years of SMCRA, there have been no proven Environmental Protection Agency (EPA) damage cases on SMCRA mines and all of the State Regulatory Authority quarterly water monitoring data has not resulted in a single instance of damage to a drinking water supply or damage to a surface aquatic ecosystem.

The volume of CCB placement at SMCRA mines is generally controlled by economics. Current or foreseeable economics of CCB placement at mines is restricted to: (1) situations of low transportation costs (i.e. mine mouth power plants); (2) very small power plants that can not afford to develop their own Resource Conservation & Recovery Act (RCRA) solid waste landfill due to the low volume of material and then only if a coal mine is close enough so that transportation is affordable; (3) a unique beneficial application at the mine justifies additional transportation cost such as use of CCBs for road building or other construction material, encapsulation of acid forming materials, and subsidence control and mitigation of acid mine drainage.