ハイウォールマイニングシステムの適用とその問題点について

Abstract

There are many sites where opencut mining operations have developed long highwalls that have been abandoned due to the economic limits of surface mining technology. Highwall mining is a technique utilized after the opencut portion of a coal seam has been mined, sometimes prior to the introduction of full-scale underground mining. In the highwall mining, the coal seam is mined by remotely operated equipment such as an auger or a continuous miner. However, a large amount of coal tends to remain isolated and undeveloped as pillars due to mining operations performed by the auger or the continuous miner. Major issues are less coal recovery and highwall instability due to pillar and roof failures of the extraction holes.Where the conventional opencut mining is difficult or impossible in a small-scale mine due to uneconomical stripping ratio, the highwall mining systems could be applied to this site. After making a small pit, the mining operation starts from the outcrop with less environmental disturbance.This paper describes highwall mining systems and their problems and also proposes new mining systems to increase the coal recovery from final highwalls with using conventional underground mining methods and equipment.