Gateway Retained Technology Along Goaf of Coal Mining Face with Thick and Hard Roof

According to the high difficulty and gateway retained serious deformation conditions of the gateway retained along goaf in the coal mining face under co nditions of thick and hard roof in Fenghuangshan Mine, in combination with the roof movement law, a blasting technology was applied to pre-fracture the roof and perio dical roof weighting of the coal mining face was applied to cut the roof along the goaf.Thus a support structure of the basic roof in the overburden strata was formed, th e rotary and subsidence deformation of the basic roof was controlled and a pressure releasing role was realized.In combination with the technical features of the gatew ay retained along the goaf in No.154307 coal mining face of Fenghuangshan Mine, a plane layout mode of the coal mining face with the gateway retained along the goa f under the hard roof condition, the backfill material width, an auxiliary enhanced support method and the roof pre-treatment means were analyzed and designed .An obs ervation and analysis were conducted on the convergence speed between the roof and floor as well as the two sides of the gateway and the surrounding rock activity la w.After the gateway retained along the goaf, the cross section area of the gateway was over 8 m2 and the roof of the gateway was completed and stable.