Mining, Metallurgy & Exploration (2019) 36:513–521, https://doi.org/10.1007/s42461-019-0058-6
Blasting is the main method of production in many noncoal underground mining operations, producing multiple toxic gases. The U.S. Mine Safety and Health Administration (MSHA) requires mine operators to measure the level of toxic gases in mines as frequently as necessary to ensure they are below regulatory safety limits. The current practice uses portable gas monitors to check the concentrations of toxic gases after a fixed post-blast time. This paper studies the application of a gas-monitoring system in the return entry of a limestone mine to determine a safe re-entry time. The study shows that the use of gas monitoring in the return air can be a useful tool at the mine operator’s disposal to detect and reduce the risk of hazardous conditions and also to reliably estimate the re-entry time.