Use of a CO2 Gas Injection System in a Laboratory Model to Study Controlled Recirculation

Abstract

Recirculation is the major concern associated with the utilization of booster fans. In controlled recirculation, a portion of the return air is purposely mixed with the intake air and the mixture is directed towards a working district, while the air quantity and gas concentrations in the air are closely monitored and managed. The objectives of this study were to determine the gas concentration in intake and return airways during controlled recirculation, and to determine the recirculation fraction for multiple headings. Experiments were conducted in a laboratory model to determine the effect of controlled recirculation on the quality of air circulated through the working faces. Preliminary results showed that recirculation is beneficial to ventilation planning because it reduces the build-up of air contaminants at the working faces and reduces the overall power consumptions. The experimental results were used to quantify the recirculation fraction and to calibrate ventilation models of the laboratory model. These models are used to simulate the controlled recirculation and to predict the gas concentrations in multiple headings.

Investigating the Impact of Caving on Longwall Mine Ventilation Using Scaled Physical Modeling

“…Jones and Lowrie made significant efforts to develop a ½0th and 1/70th scale physical model to simulate 100-m and 200-m sections of longwall face, respectively [21,22]. Gangrade et al developed 1/30th scale model of a mine section to investigate application of booster fans in coal mines [23]. Calizaya et al used a scaled coal mine model to investigate the application of pressure balancing techniques to control spontaneous combustion [24].…”