Weeks J L
United Mine Workers of America, Washington, D.C. 20005, USA.
Am Ind Hyg Assoc J. 1995 Apr;56(4):328-32. doi: 10.1080/15428119591016935.
Coal mine operators are required to sample miners' exposure to respirable dust on a regular basis. A method has been developed for screening all operator samples for detecting possible instances of fraud. This method relies on the occurrence of very low concentration (VLC = 0.1 mg/m3) samples more frequently than expected. The number of underground mine sections from which 50% or more of all samples for FY 1990 were VLC (VLC-50 sections) was compared to the expected number, which was estimated by assuming that the occurrence of VLC samples could be described with a binomial probability distribution. Out of 1983 continuous mining sections, there were 147 VLC-50 sections vs. 7.3 expected (O/E = 20.1). Moreover, these 147 sections occurred more frequently than expected among small as opposed to large mines. For sections using conventional mining methods, 19 of 175 were VLC-50 vs. 0.9 expected (O/E = 20.8). There was one VLC-50 longwall section vs. 0.003 expected. For 99 bituminous and anthracite hand-loading sections the observed number of VLC-50 sections was 65 vs. 78 expected (O/E = 0.8). It is suggested that, except for hand-loading and longwall sections, sampling programs should be investigated at mines with VLC-50 sections.
煤矿经营者必须定期对矿工接触可吸入粉尘的情况进行采样。已开发出一种方法，用于筛选所有经营者的样本，以检测可能的欺诈情况。该方法依赖于极低浓度（VLC = 0.1毫克/立方米）样本的出现频率高于预期。将1990财年所有样本中50%或更多为VLC的地下矿区数量（VLC - 50矿区）与预期数量进行比较，预期数量是通过假设VLC样本的出现可用二项式概率分布来描述而估算得出的。在1983个连续开采区中，有147个VLC - 50矿区，而预期为7.3个（观测值/预期值 = 20.1）。此外，与大型矿井相比，这些147个矿区在小型矿井中出现的频率高于预期。对于采用传统采矿方法的区域，175个中有19个是VLC - 50矿区，而预期为0.9个（观测值/预期值 = 20.8）。有1个长壁开采区是VLC - 50矿区，而预期为0.003个。对于99个烟煤和无烟煤人工装载区，观测到的VLC - 50矿区数量为65个，而预期为78个（观测值/预期值 = 0.8）。建议除人工装载区和长壁开采区外，应对有VLC - 50矿区的矿井的采样计划进行调查。
