Studies of TBM rock cutting and frictional ignition control in underground coal mines

Great consumption of coal has transformed the underground coal mining industry with new features. The first is the increasing depth of cover of coal mining operations due to shallow resources being exhausted. Some operations overseas have been operated at an overburden of more than 1300 meters. The second feature is the intensified production concentration associated with the greatly improved advancing rate of longwall faces； a single face output has reached more than 10 million tonnes per annum. Deep operations are exposed to a high ground stress regime, high gas content, and coal and gas outburst risk. These issues cause changes in mine design, including but not limited to high demand for stone roadways， which are more stable than coal ones under high ground stress conditions. Stone gate roads are needed to accommodate cross measure drilling to protect coal gate drivage from the risk of high gas emissions and outburst hazards. Increasing longwall face advancing rate shortens the lifespan of panels. Further, it necessitates short longwall development time to achieve smooth panel succession. Improved coal gate development and stone gate development are essential to fulfil this requirement. A Tunnel Boring Machine (TBM) is a kind of tunnel construction machinery which integrates the functions of excavation, ground support, mucking, lining， and surveying. It can achieve much higher heading rates than conventional drill and blast and roadheader methods, consequently, it has been proposed to be employed in underground coal mines to accommodate the requirement of high development rate.