Comparison of mine re-entry time for Forcing and Exhaust Ventilation Systems

Author: Akash Adhikari, Department of Mining Engineering and Management

Mentor: Dr. Purushotham Tukkaraja, Department of Mining Engineering and Management

In underground mines, blasting-induced pollutants (dust + fumes) need to be diluted and removed from the working area within a reasonable time frame. If a miner re-enters the working area too soon after a blast, it can cause health and safety issues. On the other hand, overestimating the re-entry time can cause production delays, inefficiency, and an increase in ventilation cost. Most underground mines still simply standardize re-entry times based on experiences and observations, often resulting in an erroneous selection of the re-entry time. Few mines use theoretical methods; however, they cannot account for changes in blasting conditions.

In this research, a computational fluid dynamics (CFD) method is used to understand the fume flow behavior in the mining environment, i.e., predicting where and how the fumes flow after an underground development blast. CFD is preferred over the traditional methods because a wide range of scenarios can be tested and analyzed quickly and accurately in physically restricted areas such as in underground mine environments. The re-entry time for forcing and exhaust ventilation systems are compared. The forcing system was found to be eight times faster than the exhaust system. Therefore, when appropriate, forcing ventilation systems should be considered to increase the ventilation efficiency and reduce operational delays.