Roof Support Technology of Open-Off Cut for Fully Mechanized Coal Mining Face Under Goaf Area

In order to study the roof support technology of the open-off cut for the fully mechanized coal mining face under the goaf,according to the 6.5 m width open-off cut of No.3-101 fully mechanized coal mining face in Beiyu Mine,a face roof distance of 0.8 m to above seam goaf and the watery softened floor features of the above goaf,based on the engineering analogy,the W-type steel bands and the 2.5 m long hydraulic swelling anchors were applied to the combined support of the open-off cut of the coal mining face under the above seam goaf.The space between the bolts was 750 mm and the row space between the bolts was 500~700 mm.The two side walls of the open-off cut could not be supported.After the combined roof support technology applied to the site operation,the max relative convergence between the roof and floor of the open-off cut was 75 mm.Thus the roof support problem of the open-off cut for the fully mechanized coal mining face with a extreme short distance to the above seam goaf was effectively solved.