Study on Strata Behaviors of the Coal Face with Sublevel Caving in Hugely-Thick Coal Seam in Qianqiu Coal Mine

Abstract

Qianqiu Coal Mine, Yima Coal Group Company Limited, China, has been mining the gently-inclined and hugely-thick coal seam #2-3. The overburden above the coal seam has hugely-thick conglomerate strata with more than 400m thickness, which has significant effects on the strata behaviors of the coal face with sublevel caving. Therefore, study on strata behaviors has an important practical significance to surrounding rocks control and safety production at the coal face. Using theoretical analysis and field observation methods, the following conclusions can be drawn: (1) the surrounding rocks of the coal face with sublevel caving belongs to difficult control one, i.e., it is the surrounding rocks control of roof and floor at the coal face that is difficult. At last, hydraulic supports with sublevel caving of pattern ZF7000-18/28 and their reasonable matching equipment were chosen. (2) The law of strata behaviors of the coal face was observed. Strata behaviors of the coal face were significant and inconsistent at different coal face zones. The parameters of roof weighting interval and roof weighting strength at the coal face were obtained. The maximum value of supporting resistance during periodical weighting was 4307.70kN, being 61.54% of supports rating resistance. Therefore, the supports at the coal face had a higher reliability. Mine production-model with one-mine and one-face can be realized, which promotes the construction of a modernization mine with high production and high efficiency.