The risk of heat exhaustion at a deep underground metalliferous mine in relation to surface temperatures

The risk of heal exhaustion at a deep underground metalliferous mine was as sessed in relation to thermal conditions prevailing on the surface. For eac h day of a 1-year prospective case series of heat exhaustion, surface 24-h mean wet and dry bulb temperatures were recorded. From this data, 24-h mean wet bulb globe temperatures were derived using certain assumptions. The th ree surface temperature variables were significantly higher on those days o n which heat exhaustion occurred. compared to those days on which it did no t occur (P<0.001). The relative risk of heat exhaustion on days when the 24 -h mean wet bulb globe temperature was in the range 26.0-28.0 degrees C was 4.82 (95% confidence interval 2.12-10.96). Surface temperature data could be used at this mine to warn miners about the risk of heat exhaustion.