Study and Practices on Changing from Fully Mechanized High Cutting Coal Mining to Fully Mechanized Top Coal Caving Mining in Buertai Mine

During the mining processes of No.42101-1 and No.42102-2 fully mechanized high cutting coal mining faces in Buertai Mine,there were serious roof falling,spalling and other strong roof strata pressure behaviors occurred and the coal mining faces were hard to have a safety and high efficient mining operation.Therefore,a study was conducted on the feasibility of the fully mechanized top coal caving mining technique selected for a new coal mining face in No.4-2 seam of the mine.The multi factors fuzzy comprehensive judging method was applied to judge the mining depth and the uniaxial compressive strength ratio,parting strength,mining and caving ratio,seam joint crack interval,parting thickness,caving membership of the main roof lithology and base roof lithology.The caving comprehensive membership of No.4-2 seam was 0.82-0.85 and the seam would have a good caving.The roof structure parameters of the fully mechanized top coal caving mining face and the site measured mine strata pressure parameters of the high cutting fully mechanized coal mining face combined could predict that the support strength of the powered support for fully mechanized top coal caving mining face in No.4-2 seam was 1.36-1.39 MPa.The actual mining of the fully mechanized top coal caving mining face showed that the mine strata pressure behavior of the mining face was normal,the production of the mining face was 0.524-0.631 million tons and the high production and high efficiency was realized in the coal mining face.