Utilization of Historical Subsidence Data for Prediction of Adverse Subsidence Conditions over Trona Mine

After longwall mining, the ground subsides. Estimating the magnitude and the shape of mine subsidence ground movement profiles is critical in assessing the likely damage potential to the environment and surface structures or buried pipelines. There are two approaches to estimating these ground movements: empirical and analytical methods. The empirical approach is based on statistical solutions using ground movement measurement data to construct the displacement field, whereas the analytical method includes closed-form solutions or computer modeling to generate the estimated ground movement fields. In this study, the effect of longwall mining on the surface movement is evaluated for a trona mine using an empirical approach. This empirical approach allows for more realistic understanding of the historical adverse subsidence-induced movements. In the studied areas, the mine depths range from 460 to 520 m with panel widths of about 150–240 m. The chain pillars were typically 30 × 60 m. Subsidence data that were available for analyzing the response of surface structures covered three basins. Basins 1, 2, and 4 consisted of 11, 3, and 11 longwall panels, respectively. From measured subsidence data, the adverse subsidence profile conditions were reviewed and analyzed. Both vertical and horizontal displacement fields were estimated. Using this empirical approach, which is discussed in the paper, a reasonable estimate of adverse ground movement due to mining subsidence from future mining for the studied case is provided.