ABSTRACT
With the increasing of mining depth, more and more mining activities are being conducted in deep strata. A series of hazards such as rockburst, large deformation, and collapse occur frequently in deep mines. Researches show that the main reason causing these deep mine hazards are related to the high stress level environment. Therefore, innovating the mining technology is one of the important ways to mitigate and to reduce mine hazards. In this paper, a study about the longwall mining method is presented in order to permit solving these high stress problems. The traditional longwall mining method was introduced at the beginning of 18th century the so-called as 121 mining method (1 working face, 2 excavation gateways and 1 remaining coal pillar). The method was widely used in China. According to the statistics in coal mines, more than 92% of the accidents occurred during the excavation of gateways. To reduce mining accidents associated with longwall mining method and to increase the productivity of the mining explorations, the author proposed a new longwall mining method in 2008, called the 110 mining method (1 working face, 1 excavation gateway and no coal pillar), including directional pre-splitting cutting and the use of large deformation bolt/anchor supporting systems. Using the new method, 50% of the gateways are no longer needed to be excavated; instead, they are formed by a controlled roof collapse. By reducing the need for gateway excavation, mining accidents and consequently costs could be significantly decreased. In this sense, the third mining technology revolution is underway in China.
