Monitoring airborne contaminant levels (1)

The mine operator of a mine must ensure that air monitoring is carried out to determine the airborne concentration of a substance or mixture at the mine to which an exposure standard applies if —
(a) the mine operator is not certain on reasonable grounds whether or not the airborne concentration of the substance or mixture at the mine exceeds the relevant exposure standard; or
(b) monitoring is necessary to determine whether there is a risk to health.