A field evaluation of the BGI and cowl type gravimetric samplers

Abstract

After initial studies by the CSIR indicating that a discrepancy exists in the dust concentration results between gravimetric dust samplers, alternative instruments or methods were sought. In the study that followed; it was recommended by the HSL in the UK that a cowl arrangement, together with a sampling rate equivalent to the CEN / ISO standard, be used to minimize over sampling. As such CEN/ISO recommended sampling rate of 2.2 l/min was used for the first time in South African mines. A BGIstainless steel cyclone sampler and a Higgins Dewell type sampler with a cowl arrangement were used in the study. Implementation of the recommended changes to samplers and the flow rate will interrupt the continuity of monitoring data built up over the years, but they will raise South African dust measurements to international standards. Although extensive work has been carried out on the use of cyclones, most of the previous studies were carried out in the laboratory, which have an advantage over the extremely difficult conditions in underground coal mines. This paper describes the field results from the two gravimetric samplers tested underground.