Deep mines often require cooling to comply with local heat stress regulations. Attempts to mitigate heat strain via improved heat indices are well documented. However, the impact of heat-stress index on refrigeration capacity is less explored. The paper examines the refrigeration capacity necessary to develop a 1.5 km deep mineshaft as a function of wet bulb globe temperature (WBGT) and wet bulb temperature (Twb). Thermodynamic simulations in Ventsim indicated chiller capacity sized from a sigma-heat (σ) balance was insufficient to prevent elevated heat stress, at working depth, according to the WBGT. The study revealed that enhanced wet-bulb depressions, associated to an overwhelming percentage of sensible to total heat ratio, was the primary factor. Furthermore, the work investigated active engineering controls like increased airflow quantity, duct insulation, and secondary cooling to satisfy refrigeration equipment constraints, such as minimum collar Twb, and ventilation design criteria. Additional research is necessary to develop empirical methods that could facilitate the prediction of cooling requirements for mine sites that do not employ Twb as the design heat index.
