Experimental Study on the Compaction and Deformation of Filling Gangue by Reducing Waste Gangue for Filling Mining

Abstract

The coal mining technology of fully mechanized solid filling is an efficient and green mining method that integrates “sediment reduction” and “emission reduction.” However, the discharge of wasted gangue and surface subsidence are controlled by the amount of wasted gangue used in filling mining and the compaction rate of gangue filled into a goaf, respectively. To increase the consumption of wasted gangue and reduce surface subsidence, mixed gangue composed of equal-quality washed gangue and crushed gangue is proposed as a raw material for solid filling on the basis of gradation theory. Next, a screening experiment was performed to analyze the grain gradation of different specimens, and a compression experiment was executed to compare and analyze the compression characteristics. The results show that the nonuniformity coefficient of mixed gangue is 55.2 and the curvature coefficient is 1.53, which significantly improve the grain gradation of washed gangue. The degree of relative compaction of mixed gangue is 1.226, which is significantly lower than that of washed gangue, which is 1.33. The deformation modulus of mixed gangue is 23–135 MPa, which is better than that of washed gangue (26–100 MPa), indicating that the compressive resistance of mixed gangue is significantly improved. The case study of the Tangkou mine suggests that mixed gangue greatly promotes the consumption of wasted gangue and can effectively control the surface deformation.

Study on the macro–micro evolution of compaction characteristics of coal gangue with different grain sizes under side-limit compression conditions

“…With the long-term sustained development of coal resources, the continuous underground coal mining activities have caused surface subsidence and accumulation of coal gangue waste, which has seriously affected coal mining and caused serious pollution to the living environment in mining areas 1 – 4 . Fill mining, as a green mining technology, utilises coal gangue underground for filling in order to reduce problems such as difficulty in accumulating coal gangue on the surface and pollution of the environment, to improve the recovery rate of coal resources and to control surface subsidence 5 – 7 .…”

Research on the bearing creep characteristics and constitutive model of gangue filling body

“…They found that as the particle size of gangue increases, the gangue particles are more susceptible to experiencing force chain instability and failure. Dong et al 28 , 29 proposed using both washed gangue and crushed gangue as solid filling materials. They employed a similar gradation method to prepare test samples and conducted combined compression tests to compare and analyze compression characteristics.…”

Grouting mechanism and experimental study of goaf considering filtration effect

“…Large-scale and high-intensity mining activities and the utilization of coal resources have produced a large amount of solid waste of coal gangue [1][2][3], occupying a large number of land resources and polluting air, groundwater and soil, resulting in a series of ecological, environmental problems [4][5][6]. The coal gangue and water are mixed into a certain concentration of gangue slurry through the underground slurry preparation system, and the goaf caving zone is filled with adjacent grouting to realize the harmless disposal of coal gangue under the low interference condition of the working face [7,8].…”