1. Correlating variability of the leakage characteristics with the hydraulic performance of an auxiliary ventilation system (Completed)
Ventilation is one of the key factors in controlling underground working environment by providing sufficient amount of fresh air for breathing, dispersing harmful gasses and dust and to some extent for heating/cooling. Insufficient airflow is dangerous for the working face and can lead to fatalities. Duct leakage is the most common reason for the insufficient fresh air in underground working and has been the subject of many studies in the literature. The main focus of the past studies, however, had been on ascertaining its impact on the ventilation requirements of the underground environment. This project identified key variables associated with duct leakage that significantly impact the power consumption levels of auxiliary fans which form an integral part of the underground ventilation system. A three-dimensional Computational Fluid Dynamics (CFD) modeling approach was undertaken in conjunction with Monte Carlo simulations and multiple regression analysis to quantify the effect of duct leakage on the fan operating point and discharge flow rate towards the working face. Various cases involving the positioning, orientation, and size of the rupture in the ventilation duct are simulated, and their respective effects on fan operating point and power levels were determined. Key results indicated that the operating point of a fan for ventilation ducts is strongly correlated with the position and size of the rupture, resulting in reduced delivery of ventilation air towards the working face for different levels of fan power consumption.
2. Prediction of air flow, methane, and coal dust dispersion in a room and pillar mining face (Completed)
In underground coal mines, uncontrolled accumulation of methane and fine coal dust often leads to serious incidents such as explosion. Therefore, methane and dust dispersion is closely monitored and strictly regulated. Accordingly, significant efforts have been devoted to study methane and dust dispersion in underground mines. In this project, methane emission and dust concentration were numerically investigated using a computational fluid dynamics (CFD) approach. Various possible scenarios of underground mine configurations were evaluated. Key results showed that the presence of continuous miner adversely affects the air flow and leads to increased methane and dust concentrations. Nevertheless, it is found that such negative effect can be minimized or even neutralized by operating the scrubber fan in suction mode. In addition, it was found that the combination of scrubber fan in suction mode and brattice results in the best performance in terms of methane and dust removal from the mining face.