In order to realize the roof caving in time during the mining of coal seams with hard roof,taking 7505 fully-mechanized mining face as the research object,deep-hole blasting was proposed to weaken the roof at the mining face,and engineering application was carried out.In the 7505 fully-mechanized mining face,holes with a depth of 9 m were arranged according to 4-5 m spacing,and holes with a depth of 9.6 m were arranged according to 2-3 m spacing in the mining roadway.The uncoupled charging method was adopted,and the specific charging structure of powder charge holes was proposed.After the field application,it was found that the cracks in the roof expanded and the strength and integrity decreased obviously;the first pressure step after mining face would be 24.2-27.8 m,the goaf roof hanging area was small,and the roof can caving in time,creating a good condition for safe and efficient mining of 7505 fully-mechanized caving face.The research results can provide experience for roof management in other mines during hard coal seam mining.
维普
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