Optimization and practice of supportworking resistance in fully-mechanized top coal caving in shallow thick seam

Abstract

Based on the overburdened structure of shallow coal seams in the West of China, the traditional support resistance method may not apply in such regions due to many roof shear and support crushing accidents. Four support working resistance indexes-rated working resistance, average working resistance, average-partial working resistance, and average-upper working resistance are counted as the candidate working resistance. The method of optimizing and inverting working resistance was put forward based on the roof control effect and working resistance overrun percentage. The simulation of a fully-mechanized top coal caving working face was built by using the UDEC software to analyze the top coal cavability and roof subsidence under different supporting strengths to determine the final working resistance. The project practice of 1322 working face in Jindi coal mine shows that the working resistance is 80-90% of calculated rated working resistance. The hydraulic support is worked under good condition. There is no pillar shrinkage and support crushing during coal mining.