Effective evaluation of deep-hole blasting for controlling strong tremors induced by deep coal mining-A case study

Abstract

As the coal mining goes deeper, strong mining induced tremors frequently occur, which seriously threaten the safety of underground miners and ground residents, as well as the productivity and effectiveness of mining activities. The deep-hole blasting technology is expected to weaken or fracture the roof, thereby reducing the risk of strong mine tremors. However, the effectiveness of this technology lacks systematic study. This paper investigates the characteristics of mine tremors and stress distribution before and after deep-hole blasting during the mining process in Dongtan coal mine in Shandong province, China, and reveals the effect of deep-hole blasting in preventing and controlling strong mine tremors. After the deep-hole blasting, the energy and spatial distribution of the mine tremors change greatly. The energy of small mine tremors increases by an order of magnitude, but large-energy mine tremors (hazardous mine tremors) are basically eliminated. Combined with the results of stress monitoring, the deep-hole blasting technology could effectively weaken and fracture the thick-and-hard strata overlying the coal seam, so as to achieve the purpose of discharging strain energy in overlying rock. The implementation of deep-hole blasting technology will not eliminate mine tremors, but it could reduce or eliminate the strong mine tremors caused by the instantaneous fracturing of the large-scale suspended roof.