Using the Energy Index Method to Evaluate Seismic Hazards in an Underground Narrow-Vein Metal Mine Available to Purchase

A routine method of evaluating temporal and spatial changes in relative rock mass stress levels based on microseismic information was developed by NIOSH researchers in collaboration with U.S. Silver Corporation’s Galena Mine. The method is based on the Energy Index concept of Aswegen and Butler (1993), but was modified to evaluate the “running average” of inferred stress levels in a given seismogenic region for a selected time window. The new Average Scaled Energy Index method proved to be informative and efficient in providing daily information to mine operations personnel on the changing nature of stress in the rock mass due to mining and provided a standardized means to evaluate and compare conditions in different parts of the mine. It was found that underground mining crews easily understood the concept and adopted the method into daily operations. This paper discusses the initial evaluation and implementation of the modified method at the Galena Mine and provides three examples from different areas of the mine having distinct geologic and seismic characteristics to demonstrate its effectiveness.