Heat stress indices were evaluated to determine the simplest and yet sufficiently accurate method for determining heat exposure in underground mining situations. Simplicity was determined by the number of required instruments for measuring climatic factors, sturdiness and transportability of instruments, additional supplies needed, operator skills needed, difficulty of calculating from the data obtained, and initial cost. In the mine under study, the air was cooled with underground air chillers. Heat measurements did not exceed suggested levels. Relative humidity was 90 percent. There was no simple method found to obtain the desired information. Carrying, positioning and reading instruments for climatic measurements in underground mines created difficult and hazardous situations for the observers and also interfered with the activities of the miners, thus leading to incorrect data being collected. A Heat Stress Dosimeter (HSD) was designed to be worn by the miners, thus eliminating the majority of the problems encountered with other systems. The device consists of a miniaturized, self contained environmental and physiological monitoring and recording system, and was designed based upon the Vitalog PMS-8 eight channel data converter and memory.
NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio