Mining Contract: Development of a Personal Real-Time Respirable Coal Dust and Respirable Silica Dust Monitoring Instrument Based on Photoacoustic Spectroscopy

Contract #	75D30119C06204
Start Date	9/1/2019
Research Concept	Coal mine workers can be exposed to respirable coal dust when extracting coal from the seam as well as respirable silica dust, particularly when additional rock must be mined as part of the mining process. Worker exposure to one or both dusts, particularly in high levels at short intervals, can be very hazardous to the worker's health. A real-time monitor of these dusts would aid workers in evaluating their current exposure and help in determining what controls or adjustments could mitigate these exposures.

Contract Status & Impact

This contract is ongoing. For more information on this contract, send a request to mining@cdc.gov.

The long-term exposure of coal miners to excessive levels of respirable coal dust can cause coal workers' pneumoconiosis, an irreversible lung disease known as "black lung." Additionally, workers who develop black lung are at risk of other respiratory diseases, emphysema, chronic obstructive pulmonary disease, and other occupational lung diseases. Overexposure to respirable silica dust leads to silicosis—another irreversible and progressive occupational lung disease. Both occupational lung diseases can devastate a miner’s quality of life, create a heavy burden on the victims and their families, and in many cases can lead to premature death. The main goal of this research is to prevent conditions, circumstances, or events that contribute to the development of black lung or silicosis through real-time monitoring of dust levels.

The focus area of this contract research is to develop a real-time personal coal and silica dust (RTPCSD) monitoring instrument. The new monitor's dust assessment system will be based on photoacoustic spectroscopy using optical design principles. In summary, a dust sample will be injected into a RTPSCD test chamber. A laser with a specific wavelength (mid-visible to near-infrared region or approximately 660 nanometers) will be projected through two windows at opposite ends of the chamber to infiltrate the sample. Coal particles will absorb energy from the laser, causing heating of the carbon particles. This absorbed heat will create increased pressure, causing an acoustic pressure wave, which will then be measured. The results will provide information for an algorithm developed to output a dust concentration. Non-carbonate particles will be tested in a similar manner, except using a different laser wavelength (near-ultraviolet region or approximately 365 nanometers).

A prototype will be developed for lab testing and then ultimately modified for field testing in mining operations. The successful prototype will continuously measure concentrations of coal dust and silica dust in underground coal mines. The RTPCSD instrument should help mine operators to promptly identify and respond to elevated respirable coal and respirable silica dust concentrations. Using the continuous readings, the RTPCSD unit should allow mine workers to quickly evaluate the effectiveness of various dust control systems, methods, and control strategies in use.