Large deformations that accompany longwall mining result in complex spatial and temporal distributions of changes in undrained pore ̄uid pressures around the advancing face. These seemingly anomalous changes are recorded in the rapid water level response of undermined and adjacent wells, and may be explained in the short-term as a undrained poroelastic e€ect. A three-dimensional ®nite element mo...

Compared with that of equal-length working faces, the mechanical evolution mechanism overburden rocks in “knife handle”-type mining sites is more complex. The form roof fracture knife handle-type mines variable, and stress distribution near interface concentrated, thereby severely threatening safety mining. To elucidate characteristics fully mechanized top-coal caving sites, geological conditio...

During the mining process of fully-mechanized caving faces, roof roadway behind working face easily forms an arched-shape hanging structure with pushed forward, which results in potential hazards such as gas accumulation and large-scale collapse. Based on actual situation a at difficult end top coal through borehole exploration, surrounding rock displacement observation, bolt stress monitoring,...

There are two major design problems for upper seam longwall gateroads operating in a multi-seam environment. The first is to determine the location, magnitude and duration of stress transferred from lower seam mines; and the second is to predict the effect of stress transferred from lower seam mines on opening stability. To solve these problems for both longwall and room-and-pillar mines, case ...

This study systematically investigates the overburden movement and strata behavior at a fully-mechanized top coal caving (FMTCC) face in a thick coal seam in a loess-covered gullied region by field measurement and theoretical analysis. A comparative analysis was performed to examine how the attitude of surface gullies and the structure of overburden affect face support resistance. The character...

Slicing fully mechanized caving mining is a standard high-efficiency method for ultrathick coal seams. However, the effectiveness of gas control has accentuated difficulty in top low-permeability This study focused on No. 9-15 Liuhuanggou Coal Mine, Xinjiang Province, China. To this aim, results theoretical analyses and field tests were combined to explore comprehensive The (9-15)06 panel was t...

Abundant steeply-dipping thick coal seams (SDTCS) have been found in Xinjiang, China, and they are mined largely by the horizontal section top-coal caving (HSTCC) method. The hanging wall of the HSTCC face is nearly vertical and does not fracture easily after the underlying coal is extracted. As a result, stress tends to concentrate in the hanging wall of the lower-section working face (LSWF) a...