Development of a Statistical Technique for Assessing Sandstone Escarpment Stability

摘要

During the last decade, a significant amount of research has been conducted by Energy West Mining Company, government agencies, academia, and consulting companies to develop predictive tools for assessing the stability of the Castlegate Sandstone, which is found approximately 250 m above multiple-seam coal reserves. Energy West Mining uses longwall mining techniques in its operations near Huntington, Utah, and these studies were initiated to satisfy requirements for maintaining the stability of the Castlegate Sandstone and resource recovery. In this study, the authors have used multiple-regression analysis techniques and a wealth of data collected over many years on geology, mining, and escarpment stability. The volume of failed rocks is used as the response variable after several other factors were considered, including measurement of surface deformation and frequency of mining-induced surface fractures. Geologic and geometric variables were obtained along 3.7 km of escarpment exposure at 130 study locations. Regression analysis of data for the first 29 study locations, which had been fully undermined, showed that surface topography played a critical role in influencing escarpment stability. Preliminary regression analysis results from 70 study locations identified several other important geologic and mining factors that influence the stability of the sandstone escarpment. These are canyon slope, sandstone thickness, and mining influence angle.