Development of a simulation model for gas dispersion and concentration in underground mines

Abstract

The accumulation of harmful gases in underground mining operations poses significant health, safety, and environmental risks. This project focuses on developing a simulation model to predict the dispersion and concentration of gases in underground mining environments. Gases such as carbon monoxide (CO), carbon dioxide (CO₂), and nitrogen dioxide (NO₂) were characterized using real-time air quality monitors. Initial gas concentrations reached hazardous levels—CO at 80 ppm, CO₂ at 22,000 ppm, and NO at 12 ppm—exceeding occupational safety thresholds. After implementing an optimized ventilation system, concentrations significantly dropped to 32 ppm, 12,000 ppm, and 3 ppm respectively, while oxygen increased from 18% to 20.8%. Using ANSYS Fluent, a Computational Fluid Dynamics (CFD) model simulated gas dispersion across the mine layout. The simulations revealed pollutant hotspots, dead zones, and airflow inefficiencies. Key findings showed that NO accumulated near inlet zones, CO stagnated in poorly ventilated areas, and CO₂ was highest near combustion regions. The designed system required an airflow rate of 10,070 m³/min and a 75-kW fan to maintain safe air quality. A financial analysis showed that implementing the simulation-based system resulted in projected energy savings of UGX 1.5 million annually, with a break-even period of 1.67 years. The results demonstrate that simulation-based ventilation design can significantly improve underground mine safety, operational efficiency, and cost-effectiveness. Adopting such models can revolutionize mine planning and regulatory compliance.