Recoverable reserve estimation in multiple seam mines

Abstract

A reliable estimate of minable coal reserves is essential for long-term planning and for conservation of energy resources. In the majority of the world's coalfields, seams are found on multiple horizons, and coal recovery may be significantly reduced depending upon the magnitude of seam interaction. In order to evaluate the effects of interaction in terms of coal losses, a hazard technique has been developed. The first stage in this technique was to develop an efficient and accurate system to grid spatial geologic and structural information developed from randomly placed boreholes. The second stage was to utilize these gridded values to determine total available coal tonnage and chemical compositions of the seam. Depending on whether over or under mining effects are to be assessed, spatial geologic and structural conditions between the seams, are evaluated to determine if interaction is possible. Where interaction will occur, recoverable reserves are reduced accordingly. To demonstrate application of the hazard approach, potential interaction in a lower seam has been evaluated. To facilitate implementation of this reserve evaluation method under multi-seam conditions, a user-friendly computer design program, HAZARD, has been developed to calculate the recoverable coal reserves in an affected seam.