Support technologies for deep and complex roadways in underground coal mines: a review

Based on geological and mining characteristics, coal mine roadways under complex conditions were divided into five types, for each type the deformation and damage characteristics of rocks surrounding roadways were analyzed. The recent developments of roadway support technologies were introduced abroad, based on the experiences of supports for deep and complex roadways from Germany, the United States and Australia. The history and achievements of roadway support technologies in China were detailed, including rock bolting, steel supports, grouting reinforcement and combined supports. Four typical support and reinforcement case studies were analyzed, including a high stressed roadway 1,000 m below the surface, a roadway surrounded by severely weak and broken rocks, a chamber surrounded by weak and broken rocks, and a roadway with very soft and swelling rocks. Based on studies and practices in many years, rock bolting has become the mainstream roadway support form in China coal mines, and steel supports, grouting reinforcement and combined supports have also been applied at proper occasions, which have provided reliable technical measures for the safe and high effective construction and mining of underground coal mines.