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Jia J.,China University of Mining and Technology | Zhang D.,China University of Mining and Technology | Zhang D.,Sate Key Laboratory of Coal Resources and Mine Safety | Zhang D.,Xinjiang University | And 5 more authors.
Journal of Mines, Metals and Fuels | Year: 2013

The surface of Wang Jialing coal mine is widely covered by thick loess layer and gully development. For this geomorphic feature, considered the load distribution form of loess layer effect on main roof. Built 3D geological model and mechanical model of mining along gully coalface of the type "wide gully and narrow coalface". Using the stress function method and key stratum theory calculate the stress of main roof, then combining the stress with the plate theory analyzed main roof fracture mechanism, and deduced main roof fracture interval formula; using FLAC3D numerical simulation software further study main roof fracture characteristics and its disturbance on surrounding rock. The results showed that the first time fracture of main roof form shape O destruction area, and the peak value of lateral abutment pressure in the two sides of coal pillar present the regularity of periodic variation. The ground pressure measurement shows if the height of caving zone and cracked zone caused by mining reach to the surface loess layer and lead to the surface subsidence, considering the surface load analysis main roof fracture characteristics are more close to the actual mining situation.

Ma L.,China University of Mining and Technology | Ma L.,Key Laboratory of Deep Coal Resource Mining | Ma L.,Sate Key Laboratory of Coal Resources and Mine Safety | Zhang D.,China University of Mining and Technology | And 8 more authors.
Energy Education Science and Technology Part A: Energy Science and Research | Year: 2012

Based on the analysis of overburden strata structural features of typical shallow seam with thin bedrock, we introduced the connotation and definition of Aquifer-protective mining and discussed the coupling relationship between key layer of typical shallow seam and overlying strata. By using mechanics model of plate, we studied the typical shallow seam main roof key stratum broken process, illustrated the coupling broken relationship with underlying or overlying rock strata and discussed the structure of key stratum, aquifer and aquiclude coupling effects as well as the possibility of realizing aquifer-protective mining with corresponding measures. The results show that typical shallow seam with longwall mining would lose water resources inevitably. But by reducing mining height, accelerating the advancing speed, etc., before the first weighting of coalface roof after water level fell that caused by mining, it could recover soon; Even if it could not, it still doesn't affect normal capacity of water supply, at least satisfy the ecological demand for phreatic water. Therefore the purpose of typical shallow seam aquifer-protective mining may be achieved. © Sila Science. All rights reserved.

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