Models of methane behaviour in auxiliary ventilation of underground coal mining

Studies have been conducted in a roadway excavated in a coalbed of a deep underground coal mine located in Northern Spain (Hullera Vasco Leonesa SA), by both airflow velocity and methane concentration measurements. Modelling of ventilation and methane behaviour of that roadway by Computational Fluid Dynamics (CFD), through software Ansys CFX 10.0, is presented. A good correlation was found between the experimental data and the results predicted by CFD. Then a comparison of the results obtained by conventional methods with the results obtained by CFD 4D modelling, for the auxiliary ventilation in a dead-end roadway, was made. Although conventional methods give satisfactory results when considering methane dilution, this research proves that there may be some roadway zones in which methane concentration is higher than regulation values. This is owing to the airflow and methane behaviour in the roadway with the presence of dead zones, and the fact that only a part of the airflow provided by the fan reaches the working face. CFD modelling allows us to know in which zones of the roadway it may be necessary to reinforce forcing ventilation by additional systems, such as a forcing system with exhaust overlap, jet fans, spray fan systems or compressed air injectors. (C) 2009 Elsevier B.V. All rights reserved.