1.School of Engineering and Technology, China University of Geosciences, Beijing 100083, China;2.Key Laboratory on Deep Geo-Drilling Technology of the Ministry of Natural Resources, Beijing 100083, China;3.The Second Exploration Bureau of China National Administration of Coal Geology, Zhuozhou Hebei 072750, China;4.China National Administration of Coal Geology, Beijing 100083, China
P634;TE922