Equipment Selection of Hydraulic Fracturing Hard Roof in Fully Mechanized Face at Initial Mining data.docx

16 hydraulic fracturing holes were designed in 1310 fully mechanized mining face. Each hydraulic fracturing hole features with the 50～55°between drilling holes and horizontal plane, the vertial side wall of roadway, the distance between drilling holes as 10m and the depth of drilling holes as 30m. Each borehole is sealed firstly from the bottom and conducted hydraulic fracturing three times with every 3 m intervals. The sealing pressure of sealing hole pump injecting clean water into the Hole-pacher is 13-14 MPa. The criterion for the end of hydraulic fracturing is that the water gushing around the hydraulic fracturing holes (boreholes) can be seen or the fracturing sound of the roof being pre-cracked can be heard. During construction, the flow rate of the three-plunger pump ranges from 15.3 to 20.2 L/min.