In-site Measurement and Research of Top-coal Movement Law for Fully Mechanized Top-coal Caving Face in Inclined Slice of Extra-thick Coal Seam

In order to study the top-coal movement law of fully mechanized top-coal caving face in the inclined slice of extra-thick coal seam after top-coal breaking,the in-site measurement of the position of starting point,the displacement of basis points and the rate of displacement in the course of advancing of1205 fully mechanized top-coal caving face in the inclined slice was carried out by the deep base displacement tracking method in the coal mine named Huating Chenjiagou. The results showed that,in the process of advancing of the working face the top-coal of 1205 working face fell with mining,the higher top-coal started moving before the lower top-coal due to mining,the displacement and moving velocity of the top-coal in front of working face were less than that ones after the working face,this moving law of top-coal was helpful to improve the recovery rate of top-coal.