Mining Project: Understanding Elongate Mineral Particle Exposure in Mining
| Principal Investigator |
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|---|---|
| Start Date | 10/1/2018 |
| Objective |
During the mining and processing of some mineral commodities and other rock types, the potential exists to produce respirable dust containing naturally occurring elongate mineral particles (EMPs), including both asbestos and/or non-asbestos fibers. EMPs have been documented to cause lung cancer and mesothelioma in humans, in addition to fibrotic lung disease, with some estimating up to 76,700 EMP-caused lung cancer deaths between 1980 and 2009. While NIOSH estimates that 44,000 mine workers may be exposed to EMPs, little information is available on the extent to which mine workers are exposed to EMPs based on the geologies of the materials being mined. Therefore, a strong need exists for research on fundamental mineralogical properties of EMPs—relevant to toxicology, epidemiology, and exposure assessment—which industry can use as a basis for exposure monitoring and miner protection. |
Research Summary
Approach
This project plans to obtain characterized EMPs with similar physical characteristics (e.g., similar length distributions) for toxicological evaluations, and the effectiveness of separation techniques will be evaluated to achieve this goal. After EMP separation, a combination of light microscopy, electron microscopy, and x-ray methods will be used to fully characterize the sizes and mineralogy of the separated EMPs. The project will also evaluate applications of qualitative and quantitative analysis of EMPs for end-of-shift (EoS) measurement using Fourier-transform infrared spectroscopy (FTIR) analysis, fiber staining, and other novel technologies to be identified. Ultimately, the project will attempt to create a size-selective sampler that collects EMPs of dimensions shown to create health effects, improving on the current sampling method using a cowl attachment.
Milestones and Accomplishments
| Description | Audience | Year |
|---|---|---|
| Developed size separation methods for elongate mineral particles for toxicology evaluations | Academics, researchers | 2021 |
| Develop a faster fiber length and width measurement method using a commercial software | Academics, researchers | 2022 |
| Create a size-selective sampler for collecting EMPs with dimensions which cause health effects | Academics, researchers, health and safety professionals at mining operations | 2024 |
Planned Impacts and Outcomes
Through a greater understanding of the fundamental nature of asbestos and EMP exposure in the mining industry, this project will facilitate miner protection and monitoring efforts by establishing a common language around the definition of EMPs (asbestiform, cleavage fragments, etc.) and a common measurement and analytical protocol to be used by industry, academia, and government as a basis for EMP exposure monitoring and miner protection. Comparison of fiber length and width between EMPs collected using several different size-selective samplers (cowl sampler, 10-mm nylon, GK2.69 respirable and thoracic fraction) will be conducted. The respirable fraction of regulated asbestos (actinolite, amosite, anthophyllite, chrysotile, crocidolite, and tremolite) will be collected and the size separation process will be performed.
Outputs
Lee T, Ku B-K, Walker R, Kulkarni P, Barone T, Mischler S [2020]. Aerodynamic size separation of glass fiber aerosols. Journal of Occupational and Environmental Hygiene 17:(6)301–311.
Lee T, Walker R, Hummer J, Ashley E, Mischler S [2021]. Size separation of amosite by filtration and shaking methods. In Asbestos and Other Elongate Mineral Particles—New and Continuing Challenges in the 21st Century, ed. J.R. Millette and J.S. Webber (West Conshohocken, PA: ASTM International, 2021), 265–280, ASTM Johnson/Rook Conference on Asbestos July 25–29, 2022.
Lee T, Barone T, Rubinstein E, Mischler [2022]. Asbestos fiber length and width comparison between manual and semi-automated measurements. Journal of Occupational and Environmental Hygiene, 19(6):370–380.
Mischler S, Lee T [2022]. Developing a new air monitoring method for measuring occupational exposure to elongate mineral particles. ASTM Johnson/Rook Conference, Burlington VT, July 25–29, 2022.
Lee T, Walker R, Barone T, Mischler S [2022]. Airborne glass fiber aerosol separation with aerodynamic aerosol classifier and multi-cyclone sampling array. 2022 ASTM Johnson/Rook Conference on Asbestos, Burlington, VT, July 25–29, 2022.
Lee T, Walker R, Hummer J, Ashley E, Mischler S [2022]. Amosite and grunerite size separation with shaking and filtration methods. 2022 ASTM Johnson/Rook Conference on Asbestos, Burlington, VT, July 25–29, 2022.
Lee T, Barone T, Mischler S [2023]. Asbestos fiber length and width measurement between manual and semi-automated software. American Industrial Hygiene Conference and Expo, Phoenix, AZ, May 22-24, 2023.
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