Study on the Monitoring Method of Overburden Failure of Shallow Wongawilli Mining Working Face

Through the practice and improvement of Wongawilli Mining method in Shendong Mining Area, it created Shendong Characteristic short wall mechanize room mining method. Due to the shallow coal seam, the fracture zones throughout the bedrock directly after the mining, therefore the bending sinking belt didn’t exist; the conventional "three zones" theory couldn’t explain the overburden rock deformation damage rule of this situation perfectly. In order to monitor the damage of overburden strata, based on the analysis of coal pillars stability in Wongawilli working face, the paper puts forward 3D monitoring methods of overburden strata damage as follows: underground borehole stress monitoring, roof separated strata and layer's internal monitoring, surface subsidence monitoring. The set of monitoring method can monitor the instability of coal pillars, roof caving, production of separated strata in the roof, overburden rock damage and subsidence, the study is of reference and significance.