Study on Drainage of Relieved Methane from Overlying Coal Seam Far Away from the Protective Seam by Surface Well

Abstract

Based on physical and numerical simulation, it has been proved that the pressure of overlying coal seam far away from the protective seam can be relaxed completely after the protective seam has been mined out. Its relieved methane can not flow down into the working face of the protective seam but can be drained out from the “O shaped” circle of mining induced fractures by surface well. The method has been used sucessfully in Taoyuan Colliery and has provided a new way for many gassy mines in China to exploit coal bed methane resource.