Mining-induced seismicity and FLAC3D modeling at the Trail Mountain Mine.

摘要

Mining-induced seismicity (MIS) is unpredictable and has the potential to be damaging; therefore, it is important to study it to gain insight into how rock damage develops in a mine. A dataset of 1906 mining-induced events was recorded at the Trail Mountain Mine (TMM). These events cluster on Panel 13, the active panel during data collection. In this thesis, a FLAC 3D model of the mine was developed to determine if there are correlations between the seismicity and selected parameters from the model.;A model of a single longwall panel indicates that stresses in the model have an error of approximately 12.5% due to limitations in the approach used to represent joints. Subsidence in the model closely matches the subsidence measured at the mine, indicating that the model captures the first-order behavior of the mine. High stress areas in the model occur on the gateroads with increasing stress toward the east side of the workings. Peaks in the maximum shear stress are followed by peaks in seismic moment, which is consistent with seismicity accompanying de-stressing in the rock mass. Some features of the seismicity could not be explained by the model, such as the cluster at the end of the panel, which is thought to have been caused by factors that were not included in the model. The model also cannot account for the absence of floor events. The reason for the difference is unclear, but it indicates that stresses alone are not a sufficient indicator of the potential for MIS. Failed zones in the model were compared with the locations and moments of the seismicity recorded on Panel 13 and were not found to relate to the seismicity. The results of this study indicate that the model is not yet sophisticated enough to understand the seismicity at the TMM, likely because several features of the mine that could potentially explain the seismicity, such as near-seam geology and older mine workings, were not included. This model serves as a foundation for future research on seismicity at the TMM and provides insight in how to develop similar models for other mines.