Preliminary exploration of the technology of coal reshaping and replacement mining of abandoned coal in goafs

Abstract

Abstract Recycling of coal resources left behind in goaf and the treatment and utilization of solid waste from mines are one topical issues faced by the global coal mining industry at present. With the annual reduction of recoverable reserves of coal resources and the dependence on coal resources that are difficult to replace, the problems have become increasingly prominent, seriously limiting the development of coal resources and the implementation of environmental protection work. In order to effectively extract high-quality residual coal resources that have not been extracted due to historical reasons such as technological limitations, the method of filling the goaf area is usually used to control the roof strata and extract coal seams. The problem of spatiotemporal interference during the filling process and the mining stage, as well as the problem of the excess shear stiffness of the filling material meeting the roof support strength, which affects the operation of the coal machine during the mining stage, urgently needs to be solved. To this end, a resource filling and replacement method for residual coal mining in goaf was proposed, and the connotation and key scientific issues of the replacement method for room-pillar type residual coal mining were systematically elaborated. The requirements for the mechanical properties of mixed coal filling materials under the control conditions of roof rock layers were given. A large-scale on-site industrial control group grouting loose coal coagulation experiment and a laboratory coal block high water material mixed coagulation curing strength experiment were conducted, Analyzed the scientific problems faced by various links in the process of coal seam reshaping and replacement mining technology(CRRM), and further proposed improvement methods, improved the technical system of filling and replacing abandoned coal, and developed new directions for efficient and safe recovery of abandoned coal resources worldwide in the future.