Mining Contract: Novel application of Fourier-Transform Infrared Spectroscopy and optical particle counting for the real-time quantification of respirable crystalline silica and dust in the mining environment
Current commercially available methods do not allow for timely or continuous assessment of Respirable Crystalline Silica (RCS) concentrations, either on site or on-person and in the breathing zone (i.e., monitor wearability for direct exposure assessment). These factors represent a substantial barrier to widespread, actionable RCS exposure assessment in mine workers. Existing technologies will be combined to produce and validate a portable real-time monitor capable of assessing mining dust and, specifically, RCS. A wearable version of this instrument will be produced and validated. The project will begin by adapting existing commercially available technologies used to assess particulate matter (PM) mass concentrations, size distributions, and composition for the real-time assessment of miners' exposures to dust and corresponding RCS, and then aims to reduce the size into a wearable form factor for personal applications.
Contract Status & Impact
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It is proposed to integrate an FTIR spectrometer and suitable light source with the hardware of an AethLabs MA200 Black Carbon instrument-- a palm sized, battery-powered, wearable, multi-wavelength instrument with a mechanized filter tape advance mechanism-- in order to realize a wearable RCS monitor. Candidate FTIR interferometers, detectors and light sources will be evaluated. In collaboration with NIOSH SMRD we will confirm wavelength specificity at the detector accomplished by means of diffraction grating, Michelson interferometer, linear filter array, tunable filters, diode, pyroelectric detectors and others to achieve optimized designs for RCS sampling and analysis techniques amenable to using a "direct-on-filter" method, and to apply those techniques to the development of the integrated analyzer. Performance comparison to laboratory grade FTIR for quantification of RCS lab generated and field collected samples will be completed.
Further development of prototype monitors, targeting a miniaturized wearable monitor for RCS, producing at least 2 units will be completed. The size of the system components will be reduced, with a target of operation through an 8 to10 hour work shift with a quick and easily replaceable lightweight battery. Ideal dimensional specifications will be identified for the product relying on examples of existing wearable mining technology such as the Thermo PDR3700 wearable dust monitor and NIOSH collaborator expertise to help guide the design. As size, weight and power are important feasibility constraints for a wearable RCS monitor, the applicability of the off-the-shelf commercially available interferometers and spectrometers that were evaluated in our miniaturization efforts will be determined. The end focus will be to ready a fully contained, reproducible device that can be used to make real RCS measurements in the smallest possible form factor.
- Best Practices for Dust Control in Metal/Nonmetal Mining
- Control of Respirable Dust
- The Effects of Low Quartz Mass Loading and Spatial Variability on the Quartz Analysis of Surface Coal Mine Dust Samples
- Evaluating Portable Infrared Spectrometers for Measuring the Silica Content of Coal Dust
- Improving Silica Dust Control Through Targeted Research
- NIOSH Hazard Controls 27 - New Shroud Design Controls Silica Dust from Surface Mine and Construction Blast Hole Drills
- NIOSH Hazard ID 1 - Exposure to Silica Dust on Continuous Mining Operations Using Flooded-Bed Scrubbers
- A Review of Occupational Silica Exposures on Continuous Mining Operations
- Silica Dust Sources in Underground Limestone Mines
- Silica Dust Sources in Underground Metal/Nonmetal Mines - Two Case Studies