Safety and protection technology of multi-coal seam mining under river

GUO Wenbing; WANG Bibi; YANG Weiqiang; HU Chaoqun

Abstract：China's Xinjiang region is drought and water shortage.As a river with important geographical characteristics and environmental impact in Xinjiang,the Aiweiergou River is of great significance to the economy and ecology of the region.Therefore,when coal mining is carried out under the Aiweiergou River,it is necessary to ensure the safety of the mine and the normal use of the river.The safety of multi-coal seam mining and river protection technology under rivers are studied by means of theoretical analysis and numerical simulation.Under the condition of multi-coal seam mining,the development height of overburden water-conducting fracture zone(11401 working face is 41.9 m,1502 working face is 110 m,11401 working face is 113.8 m)is obtained by theoretical calculation,and the profile diagram is drawn.At the same time,the numerical simulation method is used to determine the development form and height of the water-conducting fracture in the overburden rock.Finally,based on the relationship between the height of the wa-ter-conducting fracture zone(117.8 m)and the minimum coal seam burial depth(191.5 m),it is determined that the mining under the river is safe and feasible.Under the premise of ensuring the safe mining of coal seams under rivers,by analyzing the principle of separation grouting,combined with the characteristic parameters of mining influence and the engineering site,a multi-means based on separation grouting is proposed,supplemented by river seepage prevention and optimized mining design.Precise protection technology for specific surface targets within the scope of mining influ-ence.According to the actual mining geological conditions,the probability integral method is used to calculate the sur-face movement and deformation at the river channel position before and after the mining of the test mining face.The calculation results show that the maximum horizontal deformation value(2 mm/m)of the river channel does not ex-ceed the allowable limit deformation value(2.5 mm/m)of the dam body after the precise protection technology of separation grouting is adopted.Therefore,the precise protection technology of separation grouting can be realized,and the normal use of the river channel can be ensured while the underground mining is safe.Through the analysis and re-search on the safety and protection technology of multi-seam mining under rivers,it provides reference for green min-ing.