Best Practices For Dust Control In Metal Nonmetal Mining

This handbook was developed to identify available engineering controls that can assist the industry in reducing worker exposure to respirable silica dust. The intent is to identify the “best practices” that are available for controlling respirable dust level in underground and surface metal/nonmetal mining operations. This handbook provides general information on the control technologies along with extensive references.

Respirable silica dust exposure has long been known to be a serious health threat to workers in many industries. Overexposure to respirable silica dust can lead to the development of silicosis— a lung disease that can be disabling and fatal in its most severe form. Once contracted, there is no cure for silicosis so the goal must be to prevent development by limiting a worker's exposure to respirable silica dust. In addition, the International Agency for Research on Cancer (IARC) has concluded that there is sufficient evidence to classify silica as a human carcinogen. For workers in the metal/nonmetal mining industry, the Mine Safety and Health Administration (MSHA) regulates and monitors exposure to respirable silica dust through personal dust sampling. Recent MSHA personal sampling results indicate that overexposures to respirable silica dust continue to occur for miners in metal/nonmetal mining operations. From 2004 to 2008, the percentages of samples that exceeded the applicable respirable dust standard for the different mining commodities were: • 12% for sand and gravel • 13% for stone • 18% for nonmetal • 21% for metal Of the 2,407 deaths attributed to silicosis in the United States from 1990–1999, employment information was available for 881 deaths. Metal/nonmetal mining was the industry recorded for over 15% of these 881 deaths, with mining machine operator the most frequently recorded occupation. In light of ongoing silica overexposures and reported silicosis deaths in metal/nonmetal miners, an ongoing threat to miners' health is evident. This handbook was developed to identify available engineering controls that can assist the industry in reducing worker exposure to respirable silica dust. The controls discussed in this handbook range from long-used controls which have developed into industry standards, to newer controls, which are still being optimized. The intent is to identify the “best practices” that are available for controlling respirable dust levels in underground and surface metal/nonmetal mining operations. This handbook provides general information on the control technologies along with extensive references. In some cases, the full reference(s) will need to be accessed to gain in-depth information on the testing or implementation of the control of interest.

This handbook was developed to identify available engineering controls that can help the industry reduce worker exposure to respirable coal and silica dust.

Respirable dust exposure has long been known to be a serious health threat to workers in many industries. In coal mining, overexposure to respirable coal mine dust can lead to coal workers' pneumoconiosis (CWP). CWP is a lung disease that can be disabling and fatal in its most severe form. In addition, miners can be exposed to high levels of respirable silica dust, which can cause silicosis, another disabling and/or fatal lung disease. Once contracted, there is no cure for CWP or silicosis. The goal, therefore, is to limit worker exposure to respirable dust to prevent development of these diseases. The passage of the Federal Coal Mine Health and Safety Act of 1969 established respirable dust exposure limits, dust sampling requirements for inspectors and mine operators, a voluntary x-ray surveillance program to identify CWP in underground coal miners, and a benefits program to provide compensation to affected workers and their families. The tremendous human and financial costs resulting from CWP and silicosis in the U.S. underground coal mine workforce are shown by the following statistics: • During 1970–2004, CWP was a direct or contributing cause of 69,377 deaths of U.S. underground coal mine workers. • During 1980–2005, over $39 billion in CWP benefits were paid to underground coal miners and their families. • Recent x-ray surveillance data for 2000–2006 show an increase in CWP cases. Nearly 8% of examined underground coal miners with 25 or more years of experience were diagnosed with CWP. • “Continuous miner operator” is the most frequently listed occupation on death certificates that record silicosis as the cause of death. In light of the ongoing severity of these lung diseases in coal mining, this handbook was developed to identify available engineering controls that can help the industry reduce worker exposure to respirable coal and silica dust. The controls discussed in this handbook range from long-utilized controls that have developed into industry standards to newer controls that are still being optimized. The intent was to identify the best practices that are available to control respirable dust levels in underground and surface coal mining operations. This handbook provides general information on the control technologies along with extensive references. In some cases, the full reference(s) will need to be consulted to gain in-depth information on the testing or implementation of the control of interest.