High ambient temperatures combined with high surface humidity in the
north of Australia and, in particular, the northern areas of the Northern
Territory can make underground workplaces relatively inhospitable at
certain times of the year. . Woodcutters' silver/lead/zinc mine, situated some 80 km south of
Darwin, would be the most northerly underground operation of any
significance in Australia. As such, during the build up to the wet season,
it has a particular problem of ventilating a deep underground mine with
already high dry and wet bulb temperatures at the surface. The Mine Management Act and Regulations mention only that
workplaces shall be 'in a fit state for a person to work in or occupy'.
Woodcutters therefore set in progress a Heat Stress Program to endeavour
to set standards which would be more measurable and justifiable. The
aim of the program was to compile a record of ambient atmospheric
conditions in the working areas such that areas and/or work activities
generating high ambient temperatures and humidities could be identified,
quantified and qualified. Once the analysis stage of this program was completed, Woodcutters
compiled a set of recommendations for the continued monitoring for, and
control of, heat stress conditions to ensure that no underground employee
was placed at risk from 'heat stress'. These recommendations are
discussed in this paper.