Commercial software products such as VnetPC and Ventsim have become reliable modeling and predictive tools for underground mines but are limited to conditions of turbulent flow. Models utilizing computational fluid dynamics (FLUENT code) have been developed in the past for special purposes to model the laminar and transitional flows that may be encountered in sealed areas of a longwall gob but not for regular use by mine ventilation engineers as a predictive tool for ventilation system changes. The feasibility of the models being developed and maintained by mines as a predictive tool to evaluate changes to laminar flow areas of the mine are being examined. The models will provide information for gas levels, pressure differentials and other parameters in sealed and other laminar flow areas under a variety of operating conditions including gob vent boreholes, nitrogen inertization, barometric pressure changes, on-going methane emission, seal leakage and other changing conditions. The model is three-dimensional, with gob porosity and permeability applied from the results obtained from the FLAC3D code and based upon mine geological stratigraphy and actual operating design typical of coal mines in the western United States. Scenarios can be developed to predict the changes in a sealed gob due to changes in operating protocol or mining conditions. Model validation, based upon data collected from a sealed mine longwall gob, is underway.
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