Document NNkNEeYNrVXd8pq4r572YdEG8

Silica Exposure of Underground Coal Miners U.S. Department of Labor Mine Safety and Health Administration J. Davitt M cAteer, Assistant Secretary Health Hazard Information Card MSHA' s final rule on dust controls for drilling in rock underground became effective April 19, 1994. The rule is designed to protect miners from exposure to harmful amounts of dust containing crys talline silica w hile w orking on and around rock drills such as roof bolting machines. Breathing ex cessive amounts of crystalline silica during rock drilling can cause a serious and sometimes fatal respiratory disease called " silicosis" , according to the Na tional Institute for Occupational Safety and Health (NIoSh). What is silica (quartz)? The terms " crystalline silica" and " quartz" refer to the same thing. Quartz is a natural constituent of the earth' s crust and is not chemically combined with any other substance. What is silicosis? Silicosis is a disease of the lungs due to breathing of dust containing silica particles. Silica dust can cause fibrous or scar tissue formations in the lungs w hich reduce the lung' s ability to w ork to extract oxygen from the air. There is no cure for this disease, thus, prevention is the only answ er. What are the symptoms of silicosis? There are several stages of silicosis. Early stages may go completely unno ticed. Continued exposure may result in the exposed person noticing a short ness of breath upon exercising, possible fever and occasionally bluish skin at the ear lobes or lips. Silicosis makes a person more susceptible to infec tious diseases of the lungs. Progression of the disease leads to fatigue, ext reme short ness of breath, loss of appetite, pain in the chest cavity w hich all may lead eventually to death. Acute silicosis may develop after short pe riods of exposure to high levels of quartz. Chronic silicosis usually occurs after 10 or more years of exposure to low er levels of quartz. Where are miners exposed to silica dust? The most common exposures underground occur during the drilling of rock, transportation of men or material, and loading of mine material. Miners op erating equipment such as locomotives, roof bolters, continuous miners, and shuttle cars as w ell as other miners w orking dow nw ind of such equiphave a high probability of exposure. Furthermore, all miners w orking ment,at underground coal mines are at risk of being exposed to silicacontaining dust as a part of the coal mine dust. How is MSHA addressing exposure to silica dust? MSHA has published a rule w hich requires that controls be used w hen drill-ing rock to prevent miners from being exposed to dust from the drilling action. This regulation requires that dust from drilling in rock be con trolled by use of permissible dust collectors, or by w ater, or w ater w ith a w etting 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 70.400. MSHA included a provision requiring that dust collectors be main tained in operating condition and recodified the regulation as 72.630. In addition, MSHA continues to enforce the 2.0 mg/m 3 or low er 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 standard for that area of the coal mine is reduced to provide for a safe level of exposure. What can miners do to limit their exposure to silica-containing dust? Exposure to silica-containing dust at any time poses a potential health haz ard. The improper control and disposal of silica-containing dust today not only posses a hazard now , but it can continue t o cont aminate the w ork at mosphere as long as miners and equipment w ork or travel in the area. Mine operators are required to provide and assure t he maintenance and use of appropriate controls for dust w hile drilling in rock. Miners should use all available engineering controls such as dust collectors, w et drilling, and adequate ventilation w hen drilling in rock. Roof bolter operators and helpers are encouraged to either bag the dust from dry dust collection boxes and place it in the return or shovel the dust from the box against the ribs to prevent resuspension of the dust during normal mining activities. Miner operators can reduce the amount of silica-containing dust generated by stay ing in-seam w hile mining. Cutting sandstone top and/or bottom w hile min-ing generates excessive amounts of silica-containing dust. Mining and bolt-ing on cycle, to limit the number of times the roof bolter w orks dow nw ind of the miner, is another w ork practice that can low er exposures to quartz. How can a person determine if he/she has silicosis? Mine operators are required to have an x-ray program for the benefit of miners to help protect them from developing lung disease. MSHA encour-ages all miners employed at underground mines to participate in this x-ray program. All underground mines are required to have posted an approved x-ray plan that affords miners the opportunity to receive a chest x-ray at an approved facility and at the operator' s expense. An examination is increas ingly important for miners w ho have w orked in areas with a high probability of exposure to silica-containing dust. Roof bolters, transportation w orkers, roof bolter helpers, miner operators, and miner helpers are examples of some occupations that have a high probability of exposure to silica-contain-ing dust. If an x-ray show s evidence of silicosis, miners should undergo a com-plete medical examination to determine the existence of silicosis. The medi-cal examination should include: a medical and w ork history detailing expo-sure to silica dust, observation of early signs and symptoms of respiratory disease, chest x-ray, pulmonary function test (spirometry--commonly called a breathing test), and evaluation for tuberculosis. Mine operators are required to report to MSHA any cases of silicosis or other occupational lung disease for w hich a medical diagnosis or a notice of an aw ard of compensation is received involving a miner. It is MSHA' s policy under 30 CFR 50.20-6(b)(7)(ii) that a chest x-ray reading of 1/0 or above, using the International Labor Office classification system, is a reportable occupational illness for a miner w ho has a history of exposure to silica. If you have any questions about any occupational health matter, feel free to ask us. Our job is to protect your health and safety. For more informa-tion, contact your local MSHA office or MSHA's national office at (703) 235 1358.