The optimization and planning of the mine ventilation system is a key component of mine operation given that ventilation related costs can range between 20% and 50% of the total operating cost of the mine. In large opening mines (LOMs) utilizing perimeter ventilation schemes minimal guidance is available for determining optimal booster fan (BF) placements. A ventilation survey was conducted and published previously by the author which established a CFD model for a section of an underground room and pillar large opening limestone mine. In this work the previously created CFD model was utilized to investigate a total of 15 BF positions with a focus on recirculation patterns, overall airflow within the booster fan entry, and airflow around face area. It was found that the maximum airflow around the face areas can be achieved with fan positioned on the same side of the entry as face area; with the maximum airflow through the BF entry being achieved when the fan is placed in the center of the entry on the upstream side of the pillar line. The recirculation percentages were similar in all cases reaching a maximum between 35%-40% of the total air movement. However, the highest recirculation percentages also facilitated, via air entrainment, the highest airflow magnitudes through the BF entry. The booster fan's ability to stimulate airflow through adjacent entries was found to be reduced by approximately 30% for each adjacent entry. Therefore, the recommendation was given to position the booster fan within 3 entries of the face to achieve adequate airflow.

Spray freezing technology has been shown its exceptional efficiency, safety, and sustainability for underground mine heating. Designing spray freezing systems requires a mathematical model with the rigorous formulation and fast computation methods, capable of predicting performance indicators. Existing models for spray freezing often take the droplet motion and velocity distribution as a priori, thus making it less feasible in practice. In the present work, a novel reduced-order model is developed to calculate the distributions of droplet velocity and residence time for various spray configurations (namely, flat fan, hollow cone, and full cone) and droplet diameters. The velocity distributions are then incorporated into a robust heat transfer model for mine heating to improve the prediction of the droplets freezing time and overall heat transfer rate (HTR). Consequently, the residence time distribution is used along with droplets diameter distribution to calculate the ice packing factor (IPF) and cooling capacity of the system.

Computer simulations have become an important component of the technical world today and are now the intermediate/third discipline between theory and practical experimentation. New technologies can be built more easily, more accurately, and without expensive prototypes being produced. More time is required for practical simulations of complex products and processes. In using computer models for real time analysis and what-if analysis, this presents a drawback. This is tackled by methods of model order reduction.
A tool used in numerical simulations to reduce the computational complexity of mathematical models is Model Order Reduction or Reduced Order Model (ROM). ROM tries to quickly capture the essential features of a simulation and simplify a wide range of models, including full 3D simulations, systems simulations, and embedded software. In this paper we will look at the case study on an underground mine. The exhaust gases emitted by the vehicle (parked at a dead end) are considered. The ventilation duct forces fresh air through to disperse the toxic gas and keep the CO2 level within the allowable limit. This investigation assists the mine operator in understanding the CO2 concentration and determining whether to increase or decrease the fresh air flowrate.

This paper uses vortex flow modelling to find the optimal length of eddy airflow in dead-end gallery using air velocity, pressure and diesel particulate matter (DPM) simulations and field investigations. Computational fluid dynamics (CFD) modelling conducted for four different dead-end crosscut lengths (10 m, 15 m, 20 m, and 25 m), three different crosscut angles (45o, 90o and 135o) and different air velocities in adjacent galleries revealed that a distinct vortex flow develops in the dead-end crosscut. Results indicated that an eddy airflow revolved in a curved form, while the air velocity and pressure decreased towards the centre of the vortex and DPM concentration increased towards the centre of the vortex. The eddy airflow influence distance in a dead-end crosscut depends on the crosscut angle and air velocity in the adjacent gallery. If the air velocity in the adjacent gallery is one m/s and the crosscut angle is 90o, eddy airflow ventilates up to 20 m from the entrance. Though the air velocity in the adjacent gallery is 4 m/s, eddy airflow is not ventilating the crosscut after 30 m from the crosscut entrance. The eddy flow distance is lower in obtuse-angled crosscuts than the acute-angled crosscuts.