Abstract
The Mine Safety and Health Administration (MSHA) yearly performs quartz analysis on approximately 9000 respirable coal mine dust samples collected for various occupations in U.S. coal mines. All occupational quartz exposure data gathered by MSHA since 1985 have been compiled and analyzed to characterize current occupational exposures to quartz; to determine if the quartz percentages of samples collected for different occupations have changed during the period 1985 through 1992; and to study the intramine variability associated with quartz sample percentages of selected occupations. Analysis of the occupational data shows that regardless of the type of coal extraction process used, there are a substantial number of occupational samples that contain greater than 5 percent quartz and show quartz exposures that exceed 100 μg/m3. In underground mining operations, approximately 30 percent of the samples collected at the continuous-miner operator and continuous-miner helper occupations on continuous-mining operations, and at the roof bolting occupations on both conventional and continuous-mining operations, had quartz exposures exceeding 100 μg/m3. The analysis also shows that the quartz percentages of the continuous-miner operator and cutting machine operator occupations and roof bolter (DA) have increased by 0.12 to 0.19 percent quartz per year. Analysis of the data to study intramine variability showed that the percentages of quartz in samples collected on the different sections of a multisection mine were very similar. For surface mines, the occupational data show that approximately 60 percent of the samples collected at the highwall drill operator, highwall drill helper, bulldozer operator, and refuse/backfill truck driver occupations had quartz concentrations greater than 100 μg/m3. The average quartz percentage of three of the four occupations studied was found to decrease over the period studied. Only the average quartz percentage of the highwall drill operator showed an increase. Tomb, T.F.; Gero, A.J.; Kogut, J.: Analysis of Quartz Exposure Data Obtained from Underground and Surface Coal Mining Operations. Appl. Occup. Environ. Hyg. 10(12):1019–1026; 1995.
