Movement Rule of Shallowly-Buried Thick Coal Seams with Hard Top Coal and Roof

To adopt fully mechanized top caving method for the shallowly-buried thick coal seam,the hard top coal and roof fracturing and moving were observed and analyzed and the mechanical model of roof breaking established.Based on the deep-base point method,the underground pressure observing station was set up in the full mechanized top caving workface 4101 of Anjialing Mine to observe the top coals and roofs of different levels.The data about fracturing and movement condition of the top coal and roof were obtained and the movement rule was analyzed.The result shows that the top coal falls with workface advancing,and the points at which the top coal and roof start to move is quite close to the working face,with the top coal being 10 m and the roof,15 m,ahead of the working face,and the displacement of the top coal is small.Because the top coal and roof of workface 4101 can timely fall down with workface advancing,no artificial measure is needed.