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Notes:
This slide depicts the two miners we have looked at so far and the third team member monitored that day along with measurements of the environment they were in.
The third miner (blue line) was between the other two in his core temperature levels. You may notice that his line is parallel to the high stress miner’s. He did not get as hot because he started out cooler.
The red line indicates the Heat Index value of the areas they were working in. The heat index tends to exaggerate extremes as shown by a reading of 160 º F in the top of the stope. It is included here as the index most people are familiar with through it’s use by the news media.
The brown line is Wet Bulb Globe Temperature, WBGT, an environmental measure used in the NIOSH recommended standards. Typically WBGT is averaged over 1 hour periods. In this case the average WBGT was in the low 80’s, indicating a low potential stress level.
The WBGT index failed to predict the heat illness experienced by one of our three volunteers and two of the seven mine rescuers exercising on this day.
This caused us to look at other indexes, such as the PSI.