Research on Top Coal Caving Technique in Steep and Extra-Thick Coal Seam

Reasonable caving method is an important guarantee of realizing high-yield and high-efficient of the working face. Based on the specific conditions of the 2637 working face in Zhaogezhuang Mine, compared extraction rates under different top coal caving technology with field tests and similar material simulation, adopted the multi-turns interval caving method and the 0.8m top coal caving interval, and got the best sublevel height of top coal in steep seam of Zhaogezhuang Mine is 9m. The result shows that the loss of top coal caving could be controlled under 15.4%, and the mining rate of the coal mining face reached at 84.68%.