NIOSH Releases Handbook for Industrial Minerals Mining, Processing
The handbook's aim is to empower minerals industry personnel to apply state-of-the-art dust control technology to help reduce or eliminate mine and mill worker exposure to hazardous dust concentrations.
NIOSH’s Office of Mine Safety and Health Research and the Industrial Mineral Association-North America have released a handbook describing the dust-generating processes and the control strategies necessary to enable mine operations to reduce workers’ dust exposure.
Designed primarily for use by industrial minerals producers, the handbook contains detailed information on control technologies to address all stages of the minerals handling process, including drilling, crushing, screening, conveyance, bagging, loadout, and transport. The handbook's aim is to empower minerals industry personnel to apply state-of-the-art dust control technology to help reduce or eliminate mine and mill worker exposure to hazardous dust concentrations—a critical component in ensuring the health of the nation's mine workers.
The handbook’s introduction includes the following information about federal regulation and respirable dust:
Federal regulations are in place to limit the respirable dust exposure of mine workers. Engineering controls are implemented in mining operations in an effort to reduce dust generation and limit worker exposure. For the purposes of the handbook, dust is broadly defined as small solid particles created by the breaking up of larger particles. Depending on their size, these particles can become hazardous to worker health, particularly when suspended in air. The largest size particle that can be suspended in air for long periods of time from wind velocity acting upon it is about 60 micrometers (μm), which is about the thickness of a human hair.
Particles ranging from about 60 to 2,000 μm can also become suspended in air, but they only reach heights up to approximately three feet above the ground before they fall back to the surface. Particles larger than about 2,000 μm generally creep or roll along the surface due to wind velocity acting upon them [EPA 1996]. These larger particles of dust can affect the nasal passages, causing an irritated and congested nose, and might also cause an irritant cough should they deposit in the throat. Smaller airborne particles of dust, which can remain suspended in air for hours, pose a greater risk to the respiratory system when inhaled.
In general, the smaller the aerodynamic diameter of the inhaled dust particle, the more likely it will be deposited more deeply in the respiratory tract.
The handbook’s introduction emphasizes the need to control exposures to respirable silica dust. The control technologies for lowering dust levels below permissible or recommended occupational exposure limits are designed to control exposures not only to silica dust, but also to other types of dust.
Click here to access the entire handbook.