Analysis on Mine Pressure Law of Mechanized Longwall Mining Face in Shallow Depth Seam and Key Block Stability Lost

In order to study the mine strata pressure law and the roof structure stability above the longwall mining face in shallow mining depth seam,taking No.1307 longwall mining face in Yuyang Mine as the engineering background,a mine strata pressure observation plan was designed and a site observation was conducted.The summarized and analyzed the mine strata pressure law during the longwall mining in the shallow mining depth seam and the failure law of the overburden strata above the shallow depth seam.The summarization and analysis showed that the initial roof weighting step distance was 78m,the second roof weighting was at 93m when the coal mining face forward advanced and the periodical weighting step distance of the coal mining face was ranging from 6.4m to 8.1m.With the stability lost analysis on the key block,the max mining height should be less than 2.31m.The coefficient of the key block with no sliding and no stability lost shall be higher than 1 or equal to 1.