How is MSHA addressing exposure to silica dust?
MSHA has published a rule which requires that controls be used when drilling rock to prevent miners from being exposed to dust from the drilling action. This regulation requires that dust from drilling in rock be controlled by use of permissible dust collectors, or by water, or water with a wetting agent, or by ventilation, or by any other method or device approved by the Secretary that is as effective in controlling the dust to prevent dust exposures. Previously MSHA regulated dust from drilling in rock under Section 70.400. MSHA included a provision requiring that dust collectors be maintained in operating condition and recodified the regulation as Section 72.630. In addition, MSHA continues to enforce the 2.0 mg/m3 or lower standard for respirable coal mine dust. Samples are analyzed for crystalline silica (quartz) content to determine if the respirable dust standard should be reduced to control the miner’s exposure to silica. If the quartz level exceeds 5%, then the respirable dust
