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Measurement Precision with the Coal Mine Dust Personal Sampler

Abstract The purpose of this study was to quantify the precision of coal mine dust concentration measurements made with state-of-the-art gravimetric techniques and samplers incorporating flow control technology. Using a specially designed, portable dust chamber, 22 tests were conducted in an underground coal mine. Each test consisted of collecting 16 simultaneous dust samples using 16 coal mine dust sampler units symmetrically mounted in a container with a central inlet. Dust filter capsules were weighed in the same laboratory before and after exposure, with preexposure and postexposure weights recorded to the nearest microgram (0.001 mg). The average weight gain observed within tests ranged from 62 μg, collected over a 325-minute sampling period, to 6750 μg, collected over 320 minutes. Based on a weighted least-squares, repeated measures regression analysis, a point estimate for the standard deviation of error in recorded weight gain is 9.1 μg, with an upper one-tailed 95 percent confidence limit (UCL) o...