Study on ultra-contiguous steep coal seams with combined mining method

In order to solve the problems of difficult roadway layout and poor ventilation during the mining of ultra-contiguous steep coal seams(thin and thick),two t op coal caving methods including horizontal sectional step type top coal caving and false-inclined top beam overall combination suspend-shift support mining with suble vel caving were compared based on the geological conditions of the steep coal seams in Dawanqi Coal Mine in Baicheng of Xinjiang,and one method suitable for combi ned mining of ultra-contiguous steep coal seams was selected.Two ultra-contiguous steep coal seams were mined unitedly by excavating 30° inclined lane between the m and forming a U-shaped ventilation,which actually was the horizontal sectional step type top coal caving method.Results indicated that the combined mining method i mproved the working environment in coal face, and reduced the labor intensity of workers and increased the production efficiency.The extraction rate reached to 85% an d the production capacity of working face was up to 0.4 Mt/a.