Do the results of respirable dust samples obtained from direct-on-filter X-ray diffraction, direct-on-filter infrared and indirect infrared (KBr pellet) methods correlate?

Abstract

The objective of this study was to determine whether a correlation exists between the quartz results obtained from direct-on-filter X-ray Diffraction analysis, direct-on-filter Fourier-Transform Infrared analysis and indirect analysis (Potassium Bromide pellet) of respirable dust samples. Sampling was carried out to represent the conditions of respirable dust sampling within the South African mining industry. Field samples of respirable dust were taken from different commodities, with varying concentrations of silica and different mineral compositions. Each filter was subjected to the three analytical methods for determining quartz concentrations and the results statistically evaluated for a possible correlation. The analysis of control filters using all three methods produced results that were within the ± 15 per cent accuracy range required, showing a strong positive correlation between quartz results. Field samples showed a moderate to strong positive correlation between the quartz results. However, significant differences were found between the actual results. Further studies are needed to investigate factors within the South African mining environment which affect quartz results obtained from field samples.