Rock Bearing Capacity-Based Stepwise Bolting for Deep Underground Coal Roadway in China
Complicated occurrence situation of deep underground coal seams in China determines absence of a national rock classification index. Take Huainan mining area as an example, this paper aims to provide a practical method. It begins with a geo-mechanical assessment to check bolting feasibility of related rock mass. Once this is settled, roof self-bearing capacity coefficient and coal hardness coefficient which can comprehensively indicate basic characteristics of surrounding rock are integrated to classify the surrounding rock into four levels. Accordingly, stepwise bolting are provided according to dynamic combination of four basic bolting forms: super bolt assembly, cable bolt beam, high-pretension roof truss and metal chock plus grouting. An application case with rock Level III in Guqiao Mine, Huainan was introduced. Statistics show that bolt-based supporting is widely being used in more than 80% of Chinese coal mines with sound efficiency and applicability.
N. Zhang et al., "Rock Bearing Capacity-Based Stepwise Bolting for Deep Underground Coal Roadway in China", Advanced Materials Research, Vols. 255-260, pp. 3812-3816, 2011