| The sliding phenomenon between coal seam and its roof or floor is very common. Interlayer-gliding structure is the major factor that makes coal seam unstable, often caused by sudden changes in thickness of coal seam, even formed non-coal district, seriously impacting production. The interlayer-gliding structures developed strongly in Panji No.1 coal mine, manifested as coal breaking, coal quality deteriorating. The tectonic coal manifested as disorder bedding, coal breaking that present granular or powdery. The thickness of coal seam changed greatly and the thin coal zones developed, concave convex changes of roof or floor, and near the interlayer-gliding structures, there often are breaking of roof and floor, stress concentration, abnormal gas emission and threaten mine safety. Therefore, in order to provide effective geological information for coal mine safety production and planning, make geological forecasts by studying on the distribution laws of interlayer-gliding structure in the No.11-2 coal seams and discussing the relation with thin seam zone and tectonic coal for the first time.The distributing features and laws of thin coal zones and the relationship with the interlayer-gliding structures were announced by studied the spreading direction and amplitude change of the thin and thickening coal zones of the primary mineable coal bed in Panji No.1 coal mine. The distribution characteristics, developing places and thickness of the tectonic coal were obtained by distinguishing the logging curve. The distribution characteristics of the interlayer-gliding structures and the relationship with the tectonic coal were discussed. Summarized the lithologic associations and discussed the relation with the interlayer-gliding structures in the No.11-2 coal seams. In order to master and find out the distribution law and development intensity of interlayer-gliding structures, fuzzy comprehensive assessment was used. The main conclusions are as follows:(1)The main manifestation of interlayer-gliding structures are fracture interlayer-gliding structures, mainly caused by traction effects of the faults. Therefore, the interlayer-gliding structures of 11-2 coal seam in Panji No.1 mine are divided into corrugation type, fault sliding type and fracture type. The west area of the mine mainly manifests as fracture and fault sliding type, the middle area manifests as corrugation and fracture type, and the east area mainly manifests as fault sliding type.(2)The interlayer-gliding structure developed strongly in west and middle area of Panji No.1 coal mine, manifested as interlayer gliding, rumpling and breaking, associated fractures, inserting structure, denudation of coal, wavy crippling, thickening and thinning of coal, slippage of rock and coal, Cleavage, schistosity and so on.(3)The thin coal zones are formed by the sliding between coal seam and roof or floor through revealed and analyzed 19 thin coal zones of Panji coal mine. The direction of the interlayer-gliding structures and thin coal zones is to be vertical. The seam-gliding structures in middle area are more complex compared with west area. This is because the geological structures in middle area are more complex. Therefore, it shows that the interlayer-gliding structures and geological structures have close relationship. The dividing of the thin coal zone provide useful guide for the working face.(4)The main types of tectonic coal in 11-2 coal seam of Huainan Panji No.l coal mine are typeⅡand typelll, most developed at the bottom of the coal seam that caused the floor break. The main manifestation are fracture interlayer-gliding structures, make the coal seam little break. The tectonic coal in deep developed more pronounced than shallow place in middle and west areas. The east area is non-mining, the tectonic coal in shallow developed more pronounced than deep place, which the tectonic coal developed little.(5)Nine modes of lithologic association can form interlayer-gliding structures. It is easier for rock slip to occur when the lithologic associations are main roof+ coal seam+immediate floor type, compound roof+immediate roof+coal seam +immediate floor type and immediate roof+coal seam+immediate floor type. Lithologic associations of roof and floor are the precondition to the formation of interlayer-gliding structures.(6)The results from using fuzzy comprehensive assessment were similar with the results exposed by coal mine, six assessment indices, i.e. seam-gliding fault density, abnormal index of coal seam, fault density, intensity index of fault, development intensity index of structural coal, quantitative parameters of rock combination were taken to evaluate the complex degree of the interlayer-gliding structures in coal mine Good effects were obtained for predicting the development intensity of the interlayer-gliding structure in deep unmined areas in combination with geological conditions of coal mine, providing scientific references for production arrangement of coal mine. |
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