Monitoring and evaluation of ground movements above a deep longwall mine in the Eastern United States

The prediction and control of ground deformations due to underground mining are important considerations in the permitting, planning, and monitoring of coal mining operations. The prediction of mining-induced ground movements using the influence function method is a mature technology and is widely used in many coal basins around the world. Such movements mainly include subsidence, horizontal displacement, and horizontal and/or ground strain. Predictions can be accomplished using regional subsidence parameters and site-specific data. This paper presents an extensive three-dimensional surface displacement monitoring program above two deep longwall panels in the eastern United States with varying topographic relief. Monitoring was designed to cover both the dynamic ground movement component as well as final deformations. Each panel was monitored using both a transverse and longitudinal monitoring line. Movements were also measured over neighboring panels, which is typical for deep panels. The site-specific subsidence characteristics are presented and discussed based on results from the above-mentioned monitoring campaign, as well as results from long period l monitoring (i.e., 6 months prior to and 6 months after panel extraction), which is routinely conducted at critical surface structures above the mine.