Status of Ground Support in Australian Coal Mines with Reference to the Latest Research on Rock Bolting Technology

Australia ranked fifth in the world for total coal production, black and brown coal; behind China, America, India and Indonesia, and is the world’s largest exporter of metallurgical coal and the second largest exporter of thermal coal. Australian coal production is dominated by Queensland and NSW. Ground control constitutes one of the important factors in maintaining continuity of the production in underground operations, in particular the stability of roadways. Australian underground coal mines are served with rectangular shaped roadways and these roadways are supported by rock bolting with wire mesh lining. Research on rock bolting is vital to the lifelines of the underground operations. The support systems consist of primary bolting supports, which are supplemented by long cable bolts 4 to 8 m in length. Accordingly this paper reports on the latest research on bolting technology with particular emphasis on load transfer mechanism by pull testing and in shear. Bolt holes over drilled by 50 mm were found to improve bolt performance significantly outperformed those bolts installed in bore holes without over drilling.