GEOTECHNICAL CHARACTERIZATION OF THE COAL MINE WASTE DUMPS

The decline of the Korean coal industry has been drastic in production and consumption; both the number of operating coal mines and the annual production are reduced by more than 90%, in recent 10 years. This has been resulted mainly from the environmental concern and the collapse of commercial viability, which has eventually necessitated the government to implement the 'coal industry rationalization policies' to reduce coal production and close down uneconomical mines. The Sabuk mine, one of the major coal mines located in central Korea, is also expected to be shut down in the near future. Various leisure and recreation facilities are being constructed at the site, as a regional rehabilitation program. Significant increase in the coal production in the middle of 80's has resulted in waste dumps of greater height in order to occupy minimum ground area. Increase in rate of water distribution, height and rate of growth of waste dumps, affect the slope stability. Reclamation of these huge waste dumps and the proper treatment of the mine drainage constitute the most important factors for the feasibility of the whole construction plan. As a part of ongoing research on reclamation, treatment and utilization of coal mining wastes by the KIGAM, the present paper discusses various engineering characteristics of the waste materials involved in waste dump slope design and remedial measures. Geological, geometrical, and hydraulic factors, as well as the mechanical properties of the waste materials are considered for optimum slope design and construction. Different modes of possible slope failures, including circular failure, multiple block plane wedge failure and flow slides, have been investigated using a commercial finite element program, and treatments for maintaining or increasing the stability of waste dumps are also proposed.