Research on the Mechanism and Control of Spalling on 8 m Fully Mechanized Mining Face in Huoxi Coalfield

The great success of fully mechanized mining with a large mining height of 8 m and above in Mongolia and Shaanxi proves the feasibility of this technology. Although fully mechanized mining with a large mining height significantly increases the production capacity of mining areas, there are higher requirements for mining safety. Due to the special conditions of the 8 m coal seam in Huoxi Coalfield, the adoption of fully mechanized mining with a large mining height faces a serious problem of spalling. The key to whether complete equipment for fully mechanized mining with a large mining height can be adopted lies in the possibility to reduce such risks. In this paper, the mechanism of spalling on the 8 m fully mechanized mining face in Huoxi Coalfield is analyzed through theoretical analysis, numerical calculations and comparison of on-site data, and a “one point four zone” comprehensive evaluation method for coal seam at the front end of the working face is established based on the failure characteristics of the coal seam; according to the numerical simulation test results, it is believed that the presence of a dirt band in the middle and upper parts of the coal seam has a positive effect on the control of spalling; the overburden structure of Huoxi Coalfield exhibits the changes in “cantilever-instability-hinge”, and there is a risk of caving before the mining face, which exacerbates spalling; the advance blasting roof cutting of the working face has a significant effect on controlling the spalling of production coal faces. This research provides a theoretical basis and engineering reference for the treatment of spalling in fully mechanized mining with a large mining height in Huoxi Coalfield.