Surface Fracture Development Over Longwall Panels in South-Central West Virginia

摘要

The development of large open surface fractures over mined-out coal longwall panels is the focus of the U.S. Bureau of Mines report. The research concentrates on defining the fracture characteristics and their controlling variables. The investigation was conducted at two mines in south-central West Virginia. All but one of the fractures are subparallel to the trend of the underlying longwall panel. All of the fractures vary in elevation and do not parallel surface contours. The fractures are aligned with local joint trends, they correlate with longwall development, and they are situated in an increased tensional area over the mined-out longwall panels. These observations indicate that the fractures are tensional openings along preexisting joint planes possibly triggered by longwall mining.