Abstract:
Aiming at the technical difficulties of stability control of super-large backfill space and mining-backfill coordination constraints under the complex conditions of kilometer-deep mine with composite roof and large mining height in No.11 Coal Mine of Pingdingshan Tianan Coal Mining Co., Ltd., a technology of high-efficiency layered and sectional construction in super-large in-situ space combined with solid-paste cooperative backfill technology was proposed. The connotations of layered and sectional construction method for super-large in-situ backfill space, advanced vertical layered excavation-mining-bolting support technology, and inclined sectional isolation and sealing technology behind the support were elaborated in detail. Key core equipment such as the integrated machine for advanced roadway excavation-mining-bolting-drilling, and the inclined sectional isolation support behind the support was developed. The width effect of the advanced roadway was investigated, the analytical formula for the critical width of the advanced roadway was derived, and the support parameters of the advanced roadway were optimized. A “classified and zoned” support scheme for the advanced roadway with composite roof and an inclined sectional isolation and sealing scheme behind the support were established. The technological process of solid-paste cooperative backfill was designed, and a large mining height hydraulic support for solid-paste cooperative backfill equipped with suspended lateral gangue-throwing belt conveyor was developed. The mixing ratio of solid-paste cooperative backfill materials was regulated (the volume ratio of solid gangue was determined as 30% and the total volume ratio of paste and solid gangue was 63%), achieving the optimal performance of the combined backfill body. A “four-in-one” cooperative roof control system for super-large backfill space was constructed, namely, “suitable-height and high-strength coal wall + advanced roof bolting strength + high-strength support + combined backfill support”. The strata behavior characteristics and the mechanical compression deformation characteristics of the backfill body during solid-paste cooperative backfill mining in thick coal seams of deep mines show that the peak value of advanced abutment pressure is located 8 m ahead of the working face (an influence range of 20 m), the maximum roadway convergence is less than 41 mm, and the compression deformation of the backfill body is less than 15 mm, indicating an excellent overburden control effect of solid-paste cooperative backfill mining in super-large in-situ space of deep mines.