This paper proposes a new method to estimate the percentage of load carried by the gob in underground coal mines using a new parameter that introduces the site-specific overburden geology. The new parameter represents the strength and stiffness of the overburden with a single value based on the critical span lengths of individual overburden layers and the panel width. Field measurement case studies from different longwall mines with different overburden geologies were used to develop the new methodology. 2D numerical models of these case studies were verified against field measurements such as surface subsidence and vertical stresses, and the model results were analyzed to construct the new load estimation methodology. The method was then tested for practical implementation for pillar design using the LaModel program, which is commonly used in the U.S. coal industry. The results obtained from LaModel were compared with the available field stress measurements, and the new method implemented into LaModel was found to give successful results.
Full-text paper:
Mining, Metallurgy & Exploration (2022) 39:1899–1915, https://doi.org/10.1007/s42461-022-00658-1
