The purpose of this research was to develop a computer simulator for predicting the air quality in existing coal mines as well as a design aid for developing new mines. In addition to the air quantity flow, other variables of temperature, moisture, methane, and respirable dust are necessary to determine air quality. An additional feature of this simulator allows parametric studies of these variables to explore the effect that these variables have on the air quality of an operating mine system. The report points out areas where more research is needed. It covers the temperature moisture simulator, which gives the temperature and moisture content at any point in a mine; the methane simulator, which gives the methane concentration; and the dust simulator, which gives the dust concentration at any location in a mine.