Recommendations for a New Rock Dusting Standard to Prevent Coal Dust Explosions in Intake Airways

摘要

The workings of a bituminous coal mine produce explosive coal dust for which adding rock dust can reduce the potential for explosions. Accordingly, guidelines have been established by the Mine Safety and Health Administration (MSHA) about the relative proportion of rock dust that must be present in a mine's intake and return airways. Current MSHA regulations require that intake airways contain at least 65% incombustible content and return airways contain at least 80% incombustible content. The higher limit for return airways was set in large part because finer coal dust tends to collect in these airways. Based on extensive in-mine coal dust particle size surveys and large-scale explosion tests, the National Institute for Occupational Safety and Health (NIOSH) recommends a new standard of 80% total incombustible content (TIC) be required in the intake airways of bituminous coal mines in the absence of methane. Given the results of extensive in-mine coal dust particle size surveys and large-scale explosion tests, NIOSH recommends a new standard of 80% TIC be required in the intake airways of bituminous coal mines in the absence of methane. The survey results indicate that in some cases there are no substantial differences between the coal dust particle size distributions in return and intake air courses in today's coal mines. The survey results indicate that the current requirement of 80% TIC in return airways is still appropriate in the absence of background methane.