How relevant are engineering samples in the management of personal dust exposure?

A directive, legislated by the South African Department of Minerals and Energy (DME) in 1997, was introduced to reduce the dust exposures of continuous miner (CM) operators to below 5 mg/m3, when measured at the operator's cab position. The focus of this paper is to review the effectiveness of observing this rule for almost two decades and discuss industry perceptions arising from the application of this rule. The results have demonstrated that the engineering sample cannot predict the personal shift dust exposure of a CM operator. Therefore, it is recommended that the engineering sampling, as currently practiced, should be reviewed with the objective to discontinue and replace it by the approved PDM3700 real-time dust monitor.