During an underground mine fire, the presence of smoke and toxic gasses, low visibility, and changes in the ventilation system will make it extremely difficult to identify evacuation measures and optimum path to safety. This paper presents an algorithm for solving minimum cost flow network problem (MCFNP) for fire evacuations considering the distribution of toxic gasses inside the mine in real-time. The proposed algorithm will identify the optimum evacuation paths requiring minimum decision-making time. The algorithm holds data in nodes and arches accumulating values at each iteration, updating the network depending on the mine conditions. To achieve this, a fire simulation was performed in VentSim software to extract the air quantity, gas concentrations, visibility, and changes in the ventilation system data throughout the incident zone. The presented algorithm finds the evacuation paths improving time-response and comparing the decision-making of miners in a successful evacuation. The prediction of concentration of toxic gases, recommends safety path, avoids exposure to the danger zone despite the presence of shortest-path and road capacity toward surface or refuge chamber.

Unconventional gas wells are being drilled through coal reserves in Pennsylvania, West Virginia, and Ohio. The ability for both mining and gas producing activities to coexist safely is a continuing question for federal and state regulatory entities and for industry representatives. A hypothetical, gas well casing failure resulting from mining-induced ground movements could produce unsafe conditions in nearby operating mines and an explosion hazard. NIOSH is conducting research to characterize a hypothetical breach from an unconventional gas well and any resulting mine safety consequences for a range of mining conditions. These conditions include overburden depths of under 152 m (500 ft), between 152 (500 ft) and 274 m (900 ft) and over 274 m (900 ft). Multiple technical approaches are utilized to address the research questions. NIOSH is providing scientific input to our partners in the development of new guidelines for shale gas wells influenced by longwall mining. A summary of the current findings across all tasks is provided. The shallow cover site showed a one to two orders of magnitude increase in maximum permeability compared to the deep cover site. Stream valley conditions tended to retain much the maximum achieved permeability after mine by, up to 90%.

As part of its strategic transformation, Luossavaara-Kiirunavaara AB (LKAB) is currently evaluating an expansion of activities at four of its sites located in northern Sweden, encompassing production rate and depth increases at its existing underground mines, a surface to underground transition, as well as a potential greenfield operation. Ventilation modeling is part of the evaluation process and requires an extensive set of inputs.
This paper details the obtaining and assessment of geothermal gradient and thermal rock properties for each site. These parameters were not previously available yet are essential inputs for ventilation modeling and will influence future ventilation designs.
Geothermal gradients were determined through depth-temperature logging of select boreholes and validated against historical and recent measurements. Core samples extracted during exploration were analyzed using various analytical approaches, with multiple samples for each of the main site-specific lithologies selected. 
Results show depth and location-dependent differences between geothermal gradients as well as differences in thermal properties obtained, which are compared to values calculated using modal composition data for a limited set of lithologies. The potential causes of these differences and general implications for ventilation modeling are discussed and lead to recommendations for future thermal parameter studies.

Heat loads, associated with auto-compression, geothermal gradient activity, and mining equipment, can lead to high temperatures underground that require mitigation and/or refrigeration in order to create a safe working environment for miners. In this paper, temperature levels associated with heat generated from equipment and other sources are incorporated into a medium-term production scheduling optimization model (Ogunmodede et al, 2022). The resulting schedule considers temperature by production level and determines refrigeration requirements, if applicable, based on the ventilation capacity, production rates, and equipment usage. This tool can be used to evaluate numerous production and ventilation scenarios to make production-related decisions. Using a realistic dataset from an underground mine, numerous scenarios are evaluated to understand the impacts of various equipment heat loads and ventilation settings to illustrate the impacts of heat on the production schedule.