Optimal highwall thick seam mining systems considering the in-situ stress conditions

Highwall mining is to extract coal with an auger machine or a continuous miner. With the highwall mining system, there are many factors that have to be considered. Major factors are the coal recovery and the stability of the highwall. A large amount of coal remains isolated and undeveloped as pillars due to previous indiscriminate mining operations. Moreover, highwall mining causes highwall instability and surface subsidence due to pillar failures. Therefore, even in the case of thick coal seam, not multi-pass operation but single-pass operation is mostly applied and the coal recovery is very low. From these points of view, this paper discusses the optimal highwall thick seam mining systems considering in-situ stress conditions by means of finite element modeling.