Control of the difficult caving massive roof at the fully mechanized coal face

At Datong Coal Mining Administration in China, with the more extensively application of the fully mechanized mining at longwall face and the increase of the economic benefits of the enterprises, a long-term study and practice on the weakening and the supporting of the difficult-caving roof have being done to solve the problems of the difficult-caving of the massive roof jeopardized to the mining operation. The massive rock weakening is going to be an important branch in rock mass alternating engineering gradually. The tight roof weakening theory is going to be perfect, and a series of theories and techniques on the control of the difficult-caving massive roof have been formed. The theory and technology have been applied successfully in the control of the difficult-caving massive roof at longwall face in coal mine based on the study on the failure mechanism of the fracture rock mass structure, organic structure, fractal dimension and mechanic properties of coal and rock, etc.