Guide Hole and Expansion Digging Technology of Raise-boring Machine of Longwall Caving Open-off Cut at Large Inclination Coal Seam Layered Face in Dongxia Coal Mine

Because of large dip angle and large thickness seam at 37220-2 fully mechanized caving face of Dongxia Coal Mine, it's difficult to carry out open-off cut construction and support. We use raise-boring machine pilot hole with expanding mining process test and high strength anchor wire rope lift shed combined supporting method in inclination section. The result shows that this construction technology has the characters of high efficiency, safety and reliability, low labor intensity, good engineering quality and reliable supporting effect. Finally, it achieves safe and fast construction of open-off cut.