Study of strip-filling for old room and pillar mining goaf
According to the problems of land resources destruction and environmental pollution caused by the collapse of old room and pillar mining goaf, a goaf security evaluation model was established and applied to the safety assessment of a colliery in Ordos city. The results indicated that the room and pillar mining goafs in this coal mine area would fail with time passing. To solve the problems, with analyzing the structural characteristics and activation mechanism of old room and pillar mining goaf, based on the theory of strip mining, a new method of strip-filling for controlling subsidence of old room and pillar mining goaf was put forward and used in designing of the strip-filling plan of the colliery, the filling effect prediction have been worked out. It demonstrates that the strip-filling method is economically feasible.
Study on partial extraction of coal pillar under buildings
In this paper, the author discusses the partial lane extraction plan applied to exploitation of coal pillar under industrial square and living district of Quanshang coal mine. For one year, exploited coal has been up to 174.8 thousands of tons, the recovery up to 38%, the subsidence of surface up to 16 mm. In the same period, buildings on the ground have no deformation and beneficial economic and social results have been achieved.
Experiments on strength of small pillars of coal in the Pittsburgh bed
Report describes methods of testing seven small pillars in place in the Experimental mine; all pillars were square in horizontal cross section. Paper is a summary of progress in an investigation which, in so far as authors know, has had no previous counterpart.