Research on Pressure Relief Technology of Cutting Top Blasting
Aiming at the problems of high roof pressure,strong mining pressure manifestation,and large roadway deformation in 1208 mining area of a coal mine along the hollow stay lane,the characteristics of roof fracture during the advancement of the 1208 working face were analyzed,and the key parameters of roof cutting blasting were determined;After blasting and cutting the roof to relieve pressure in the 1208 working face,the initial pressure step distance can be reduced by 13.9 m,the dynamic load coefficient can be reduced by 0.5,and at the same time the large-scale collapse of the top coal can be reduced by 28 m.This shortens the time for the initial pressure and coal release,reduces the strength of the pressure,prevents the occurrence of large-scale collapse of the suspended roof,and avoids the risk of pillar collapse during large-scale collapse of the suspended roof.During the investigation of drilling,within the range of about 8 meters after the top cutting of the blasting,there were obvious cracks on the borehole wall;These cracks are caused by mining on the working face and are interconnected with each other.The top coal in the goaf is suspended in these interconnected cracks and collapses along with the faults,thereby improving the recovery rate of the coal seam.
Top cutting blastingBorehole inspectionMine pressure detectionCrack
NETL
NSTL
万方数据
