Rapid Construction and Support Technology of Large Span Open-off Cut for Fully Mechanized Caving Mining Face in Thick Seam of Deep Mine

According to the serious deformation, difficult construction and support of the large span 7 m wide open-off cut for fully mechanized top coal caving mini ng face in thick seam of a deep mine, a new high pre-stressed bolt and anchor combined support method was applied, rational support parameters were selected and b olt and anchor of high strength and high prestress technique of the mine roadway was applied. The experiment results showed that the construction and support technol ogy could effectively to control the deformation of the open-off cut, the roof subsidence value was less than 160 mm, the convergence between the two sidewalls of the gateway was less than 150 mm and the construction time was reduced by 50 days.Thus a rapid and safe construction was realized.