Study on the Compression Property of Formation Space for Theoretical Support

At present, the open stopping with subsequent filling mining of the “two step” mode has received significant attention. The recovery method entails dividing the ore block into the first step ore room and the second step ore room, mining the first step ore room initially and filling the formation space using cemented materials and then mining the second step ore room and filling the formation space using tailings. There are two questions to resolve in the tailings-filling work of a goaf. The first is making an accurate filling plan to assure the accomplishment of the work on time, which will not affect the recovery progress. The other is accurately calculating the lateral pressure that tailings exert on the cemented fill body to provide theoretical support for designing the required strength of cement filling body to assure its stability and the safety of the recovery process of second step ore room. These questions are associated with the density of the tailings. However, the open stoping with subsequent filling mining method is characterized by a high stage and long span. When the recovery of ore room is finished, the volume of the resulting goaf is large. The density of the tailings is affected by its weight and this exhibits non-linear growth as the height of the tailings increases. Therefore, to solve these questions, research is needed on the compressibility of the tailings under its weight.