Comparison of respirable coal mine dust concentrations measured with an MRE and a newly-developed, two-stage impactor sampler.

The design and laboratory evaluation of a two-stage aerosol sampler using an impaction plate for removing particles above 10 micron, has been reported. The unit was developed to provide an alternative to the two-stage sampling head used on approved coal mine personal respirable dust samplers. The new device offers the potential of increasing the analytical accuracy of samples, and of providing a device more suitable to the mining community for use in their mandated dust sampling program. This paper describes the underground sampling program conducted to establish the factor for converting respirable dust concentrations measured with this device to equivalent concentrations measured with an Isleworth 113A gravimetric dust sampler (MRE). This study demonstrated that the use of the impactor sampling head provides a viable alternative to the currently used sampling head. The results showed that comparative measurements could be linearly related for MRE dust measurements ranging from 0.5 to 5.5 mg/m3. The factor determined for converting measurements made with the new head to equivalent MRE measurements was approximately 0.5.