Optimizing fire emergency evacuation routes in underground coal mines: A lightweight network flow approach

In underground mine fires, the presence of smoke, toxic gasses, and high heat can significantly hinder the evacuees from identifying the optimal path to safety. This study presents a framework that couples a mine fire simulator software with a Ford-Fulkerson algorithm to model fire evacuations as a minimum-cost flow problem. The fire-induced risks are quantified based on the MSHA safety standards and a user-friendly FFA computes the evacuation routes. By accumulating the quantified effect of the risk exposure and updating the network depending on the mine conditions, different safe evacuation routes are identified. The algorithm is demonstrated through fire simulation data acquired from a model of the VentSim™ DESIGN software. Airflow quantity, air quality, heat, carbon monoxide concentration, and visibility obstruction are acquired from the simulations and processed through the proposed algorithm. Based on the distribution of the quantified hazards and the MSHA safety standards, the algorithm outputs optimal evacuation paths. The computed evacuation routes minimize the exposure to the fire-induced hazards while at the same time prioritize the shortest routes. The presented framework can be used for evaluating ventilation designs and emergency plans as well as in real-time self-evacuation in mine emergencies.