Computer modelling of transient heat flow in mines

Abstract

The traditional method to predict air temperatures in mine roadways is based on the assumption that the ventilation air temperature remains constant over the ventilated age of the roadway. Hence, a steady-state solution prevails. As the capital investment of providing an acceptable working environment in hot and deep mines is increasing, more accurate and reliable temperature predictions in mine roadways will be needed in future mine ventilation planning. For this reason, a transient model to predict weekly air temperatures in mine roadways is developed. The transient model is presented in the form of a computer program. It is constructed from the mathematical techniques developed for calculating the transient heat flow from strata (Cheung, 1988), conveyed coal (Cheung and Rabia, 1989) and structural steel (Maneylaws, 1988), and the empirical equations developed by Browning et al (1981) for estimating the heat from machinery. Duhamel's Theorem is used in the mathematical technique for calculating the transient heat flow from strata and conveyed coal. Details of these techniques are derived. In addition, the algorithm of the computer program is presented in terms of flow charts. Climatic investigations were undertaken at British Coal Collieries; three sites at Wearmouth Colliery, Sunderland, and one site at Whitemoor Colliery, Selby. During the investigations, temperature surveys were conducted at all the sites. Using the data collected from these sites, the transient model is validated against field measurements and agreeable correlation achieved. Moreover, recommendations are made to improve the model.