Research And Application Of Key Technology For Mixed Fully-Mechanized Mining Combined Waste Backfilling With Caving Method

Aiming at mining high gas low permeability coal seam without appropriate protection layers, the overlying coal seam with mass rock which has no outburst danger, or the overlying soft rock mass can be exploited to serve as a protective layer. When exploiting it with depressurized mining, it will produce a lot of gangue. So arranging mixed fully-mechanized workface combined waste backfilling with caving method in the high gas low permeability coal seam can achieve both the gangue produced by protect layer underground backfilling and the high efficiency mining of mixed fully-mechanized workface. According to the three main key technologies which include equipment matching, mixed fully-mechanized mining operation and strata movement at the mixed fully-mechanized workface, this dissertation introduces the principle of combined mining method. On the basis of geological condition of Pingdingshan No.12 mine, the paper also optimizes the mining technology and analyzes the strata movement at the mixed fully-mechanized workface with theoretical analysis, laboratory test, numeric simulation and engineering practice. The research results applied at Pingdingshan No.12 mine, which receives good application effects. The main achievements are as followed:(1)The paper analyses the principle of mixed fully-mechanized mining combined waste backfilling and caving method, three relatively complete systems of mixed fully-mechanized mining is proposed: broken and transportation system of filling guague, avoiding raising system of underground guague, operation system of mixed fully-mechanized mining. It also analyses and summaries the technical characteristics and key technology of mixed fully-mechanized mining.(2) Based on the selection principle and performance requirement of equipment at the mixed fully-mechanized workface, we ascertain the type of main equipment including coal cutter, scraper conveyer, backfill mining hydraulic support, normal hydraulic support and backfill scraper conveyer. Some optimizations on equipment matching were done according to practical situation.(3) The paper designs the mining technology of combined mining technology and decides the sorting method and crushing equipment of coal. We choose the mining scheme in the mixed fully-mechanized workface and get the relation curve of the length and height of the pack. We also optimize the three main mining technologies of combined mining method: the sorting system of coal and gangue, the crushing and transporting system of backfill material, the mining and backfilling system at the mixed fully-mechanized workface.(4) After some numerical simulations, we conclude the character of strata movement at the mixed fully-mechanized workface. Besides, based on the results of numerical simulation, we also get the appropriate length of backfill period and transition period of mixed fully-mechanized workface.