Exposure to silica dust on continuous mining operations using flooded-bed scrubbers.

Silicosis, a debilitating and potentially deadly lung disease, develops through inhalation of excessive concentrations of respirable crystalline silica dust. In underground coal mines, continuous miner operators have a high risk of overexposure to silica, with approximately 25% of compliance dust samples exceeding the permissible exposure limit. Continuous miners often extract high-silica-content rock from the coal seam or the surrounding strata. Large quantities of silica dust can be generated during cutting and can become entrained in the ventilating air, which can carry the dust to the breathing zones of mine workers. Over the last 15 years, the application of flooded-bed scrubbers (fan-powered dust collectors) on continuous miners has increased as mine operators expand efforts to reduce airborne dust concentrations. During the last several years, the density of the filter media in scrubber filter panels has been reduced to improve scrubber airflow. However, the reduction in filter density suggests that dust collection efficiencies are lower and thus expose mine workers to higher concentrations of respirable silica dust.