Safety Tidbit 7.10 - Coal Mine Dust Sampling

 

Safety Tidbit 7.10 – Coal Mine Dust Sampling

 

Reference: “Federal Register: Coal Mine Dust Sampling Devices.” Federal Register, https://www.federalregister.gov/documents/2010/04/06/2010-7308/coal-mine-dust-sampling-devices. 

 

This Safety Tidbit was written by my student, Mr. Cody Tumpak – a senior in the Safety Sciences Program at the Indiana University of PA graduating Spring 2022.

 

Coal miners are at risk of developing a lung disease called pneumoconiosis due to exposure to respirable dust.  National Institute for Occupational Safety and Health

(NIOSH) created the Coal Workers Health Surveillance Program (CWHSP) to evaluate coal mine workers. The program sets a guideline for workers to get a chest x-ray every five years. The testing results showed a high number of deaths. From 1970 to 2016, they found that 75,178 miners have died due to black lung. Therefore, the MSHA created the Black Lung Benefits Act to pay compensation and medical expenses for miners. This act paid out over 47.168 billion dollars in federal benefits.

 

Additionally, the risk of black lung disease is evaluated through air sampling to assess worker exposure to dust. There are several different types of dust sampling methods used within mining. The first type of dust sampler is called the Gravimetric Dust Sampler. Since the 1980s, the gravimetric dust sampler has been the most common type of personal dust sampler.  The gravimetric dust sampling method involves sampling a known volume of ambient air through a filter. The units used for the sample include the mass of dust (mg) per cubic meter (m³) of air. The pump typically operates at 1.7 liters per minute in metal and nonmetal mines as specified by the collection media. The filter is weighed before and after to calculate mass gain. This concentration is then used to determine an average dust concentration over the sampling period. The filter is processed using the XRD analytics technique for silica content. Also, the industrial hygienist must collect sufficient mass on the filter to have confidence in dust measurements.

 

Another type of sampling method is called the personal/Data RAM (pDR).  This method uses scattering as a measurement technology and employs a very small, versatile direct reading personal aerosol monitor to measure the dust in real-time. It has instant readings correlated with time and stored in internal memory. The size distribution of the dust, composition of dust, and the water mist in the air can all impact the pDR concentration.

 

The personal dust monitor (PDM) is another popular dust sampling method. The PDM became very popular within the mine operation because they had insufficient means to know their respirable coal dust exposure levels. The PDM allows miners to get accurate dust exposure data at the end of their shift. The PDM uses a tapered element oscillating microbalance to measure the mass of dust deposited on a filter and continually displays the cumulative exposure concentration data. It uses mass-based measurements to quantify the dust concentration. Then the dust measurements will be displayed on the screen and stored internally for later analysis.

 

Hope this was helpful and thank you for reading my Safety Tidbits! Comments and questions are always welcome. ~ Bryan

 

P.S. If you have a new safety or health question, please let me know.