The technological way of developing longwall mining in the small colliery of shallow seam area

the small colliery must adopt longwall mining that can form suction ventilation, which is a regulation of Security Production Committee of the State Council of the People's Republic of China. This article tries to summarize experiences of the small collieries in mining shallow coal seam in north of Shanxi Province, and suggests to reform unadvanced mining of room and pillar to longwall remaining coal pillars support mining which can largely inprove the coal recovery rate. The key technology of longwall remaining coal pillars support mining is to distinguish two kinds of coal pillars of different character between regional coal pillar and isolated coal pillar. Regional coal pillar is temporary coal pillar in mining the small district, and its function is only to ensure the safety of the roof when mining the small area, but it can collapse in proper time after mining the small area. In order to prevent the roof collapses accident, it needs to be monitored, and this article has put forward the technological foundation of monitoring the roof.