ABSTRACT
Coal seam group mining usually adopts descending mining method. However, in some historical and specific conditions, it is likely to mine the lower coal seam firstly and mining its upper seam later, which is named ascending mining method. Ascending mining method, which began in the 20 or 30’s of last century abroad, was studied in West Virginia and Pennsylvania in the USA, Silesia coalfield in Poland, Donbas coal in the former Soviet Union. By these studies, we accumulated much successful experience (Dunham & Stace 1978, Wang & Li 1995). Domestic practice of ascending mining began in 1970s, the domestic scholars also obtained some research results about ascending mining theories (Yuan 2006, Zhang et al. 2007, Ma et al. 2007). After years of research and practice, for ascending mining, domestic scholars preliminarily think that (Liu 2007): when only one seam is mined and its mining influence factor K > 7.5, the upper seam can be mined normally.
