Significant Dust Dispersion Models for Mining Operations

Posted by Stop Ajax Mine on November 27th, 2012 10:50am

We found a paper on InfoMine's website titled: "Significant Dust Dispersion Models for Mining Operations". It has a short section on the health effects of increased particulate matter. We've included it on this blog post for your review. 

If silica is a component of respirable dust, then the effects of exposure pose a very serious health concern. Crystalline silica in respirable dust causes more than 250 U.S. workers to die each year of silicosis [U.S. Department of Labor 1996]. There are three levels of silicosis: chronic silicosis, which generally occurs after 10 years of exposure; accelerated silicosis, which generally occurs within 5 to 10 years of exposure; and acute silicosis, which can occur within a few weeks to 5 years of high exposure to silica [U.S. Department of Labor 1996]. Silicosis has no cure and is generally fatal. Miners are susceptible to silicosis both when working underground and when working on the surface.

CWP, or black lung, is a chronic disease occurring in miners that typically develops over a long period of respirable dust exposure (%20 years) and is generally fatal [NIOSH 1995]. Black lung, which occurs mainly in miners who work underground, is caused when respirable coal dust is a major component in the air that is breathed. Other employees who work coal stockpiles are also susceptible to black lung.

In addition to the hazards of respirable dust to humans, many epidemiologic studies show that particulate matter less than 10 μm in diameter (PM10) also causes harm to humans. It has been shown that a 50-μg/m3 increase in the 24-hr average PM10 concentration was statistically significant in increasing mortality rates by 2.5%–8.5% [EPA 1996]. In relation to hospitalization due to chronic obstructive pulmonary disease, PM10 caused a statistically significant increase by 6%–25% with an increase of the 24-hr average PM10 concentration by 50 μg/m3 [EPA 1996]. Other studies have shown that children are affected by shortterm PM10 exposure and that increased chronic cough, chest illness, and bronchitis were associated with a 50-μg/m3 increase in the 24-hr average PM10 concentrations [EPA 1996]. Longterm effects from PM10 would depend on the amount of exposure to PM10 over the life of a person.

There are other adverse impacts from PM10 exposure in addition to the health effects. It is known that even small particles in the air hinder visibility, for the small particles scatter and absorb light as it travels to the observer from a source. This action results in extraneous light from sources other than the observed object being detected by the observer, thus impairing visibility [EPA 1996]. Climate change may also occur from PM10 exposure because the small particles in the atmosphere

absorb and reflect the radiation from the sun, affecting the cloud physics in the atmosphere [EPA 1996]. PM10 may also have an effect on materials such as paint, wood, metals, etc. The effects depend on the amount of PM10 in the atmosphere, the deposition of the PM10 on the material, and the elemental composition of the PM10.


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