Pressure Relief by Blasting Roof Cutting in Close Seam Group Mining under Thick Sandstone to Enhance Gas Extraction for Mining Safety

Processes

Chi-Min Shu¹  Fei Wang²  Ping Huang³  Kui Gao⁴  Ze-Gong Liu⁴  Jian Liu⁴ 

[1] Department of Safety, Health, and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin 64002, Taiwan;Renlou Coal Mine, Wanbei Mining Group Co., Huaibei 235100, China;School of Environment and Resources, Fuzhou University, Fuzhou 350108, China;School of Safety Science and Engineering, Anhui University of Science and Technology, Huainan 232001, China;

关键词: thick sandstone;    pressure relief;    hard roof;    vertical gas migration;    gas extraction;   

DOI  :  10.3390/pr9040603

来源: DOAJ

【 摘 要 】

Close seam group mining under thin immediate roofs and thick sandstone walls is typically performed with a strong mine pressure and gas concentration, which pose considerable risks to miners. In this study, the mechanism of pressure relief and permeability enhancement to enhance gas extraction for mining safety through blasting roof cutting were investigated through theoretical analyses, numerical simulations, and laboratory tests. The results revealed that, near the blast-hole, which produced numerous cracks, blasting disturbed the integrity of the thick-layer roofs and redistributed the stress near the blast-hole, which prevented violent mine pressure caused by excessive fracture distances on the thick and hard roofs, reduced the additional load on the support, increased vertical gas migration, and ameliorated the effect of gas drainage caused by high-level boreholes. The field applications of forced roof cutting through deep-hole blasting in the II 7₂24N face of the Renlou coal mine (Huaibei, Anhui, PR China) demonstrated that the occurrence of excessive pressure on the fully mechanized mining hydraulic support was prevented. The gas extraction volume of high-level boreholes was maintained at 6–8 m³/min; the extraction concentration was stable at approximately 35%; and the gas concentration in the upper corner of the coal face was lessened from 7% to <1%, which ensured normal mining in the coal face. The current results can provide data reference and a theoretical basis for roof management and gas control of the same type of coal face.

【 授权许可】

Unknown