Feasibility discrimination method of upward mining in close-distance coal seam based on data statistics

This paper investigates the common methods for assessing the feasibility of upward mining in closedistance coal seam,and analyzes the applicability and limitations of existing evaluation methods under the background of increasingly complex geological conditions and increasing mining height of the lower coal seam. Based on abundant cases statistics of upward mining in close-distance coal seams,it proposes that the upper coal seam step subsidence is the core index to assess the feasibility of upward mining of close-distance coal seams. A large number of numerical simulation tests were carried out using the UDEC code,prediction formula of upper coal seam step subsidence including thickness of the lower coal seam,coal seam spacing,the interlayer lithology index as parameters was constructed. Synergistic relationship between the step subsidence and a single parameter was obtained. Finally,the feasibility discrimination method of upward mining of close-distance coal seam based on massive data statistics is proposed. This method has high reliability,strong applicability and simple operation,which has certain theoretical and practical value. It has been used to guide the engineering practice,and the field application effect is good after verification.