Hydraulic fracturing technology for hard roof of working face with large mining height
This article focuses on the problem of difficulty in crossing the hard roof of the goaf in the triangular area of the machine head during the mining process of working face with large mining height with one mining full height.By testing and analyzing the structure and strength of the overlying strata,combined with the characteristics of the coal seam roof and the impact of fracturing density on the fracturing effect,the segmented hydraulic fracturing technology scheme is determined to be adopted,and the test on the hydraulic fracturing control of hard and difficult crossing roof is conducted on the under-ground site.The results show that after use of hydraulic fracturing technology,the roof of the goaf at the end of the working face can collapse timely,and the suspended roof area is significantly reduced.The maximum length of the suspended roof a-long the goaf at the end of the working face is generally not more than 9 m,and the maximum length along the direction of the working face is not more than 6 m,with a reduction of over 70%.In most cases,the roof can collapse timely with mining with good effect.
large mining height with one mining full heighthard and difficult crossing roofhead triangle areahydraulic fracturing