Mining Project: Understanding Elongate Mineral Particle Exposure in Mining

Principal Investigator
Start Date 10/1/2018

To facilitate monitoring efforts by establishing a common language around the definition of elongate mineral particle (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, which will ultimately benefit miner protection.

Research Summary

During the mining and processing of some mineral commodities and other rock types, there is the potential to produce respirable dust containing naturally occurring elongate mineral particles (EMPs), including both asbestos and/or non-asbestos fibers. In 2011, NIOSH estimated that 44,000 mine workers may be exposed to EMPs, in addition to 568,000 and 114,000 workers in the service and construction industries, respectively. EMPs have been documented to cause lung cancer and mesothelioma in humans in addition to fibrotic lung disease (asbestosis), with some estimating up to 76,700 EMP-caused lung cancer deaths between the years of 1980 and 2009.

Unfortunately, there is little information available relating the geologies of the materials being mined to the potential for EMP exposure to mine workers. There is a strong need for research on fundamental mineralogical properties of EMPs—relevant to toxicology, epidemiology, and exposure assessment—and their geographic distribution, which industry can use as a basis for exposure monitoring and miner protection. In addition, there is a need for improved analytical techniques for measuring EMP exposure and for consistent nomenclature, comprehensive characterization of minerals, and standardized reporting in the literature. Based on the competencies and knowledge about EMPs and mining expertise and the minerals laboratory at the Pittsburgh Mining Research Division, Bruceton, PA, NIOSH is well established to lead this research.

This project has three research aims, which will be undertaken as described below.

 (1) Assess miners’ potential exposure to asbestos and other EMPs by analyzing bulk material samples previously collected from copper, granite, gold, iron, limestone, sand and gravel, coal, and other types of mines across the country. This analysis will be driven by establishing geological knowledge of the deposits and their host rocks, which will enable strategic characterization of EMP-bearing strata. Through this research, the relationships between deposit type and EMP existence can be established, to recognize consistent and predictable associations between EMPs, ore deposit types, and geology. The bulk material samples to be analyzed were collected during previous NIOSH projects. In addition, samples collected during the National Occupational Health Survey of Mining (NOHSM) will also be analyzed. During this analysis, every effort will be made to differentiate between measured naturally occurring EMPs resulting from geologies of the rock being mined versus commercial asbestos fibers derived from mine equipment, insulation, or other activities. This information may be incorporated into a GIS database used for mapping geologies with the potential to contain EMPs, work to be completed in collaboration with the University of Minnesota, Natural Resources Research Institute (NRRI). The associated output will be a database of mine geologies with the potential to contain EMPs.

(2) Further elucidate the toxicology of EMPs by creating new separation methods to allow both in vitro and in vivo toxicity tests on EMPs of specific lengths, widths, mineralogy, and other characteristics of concern. This aim will focus on creating novel separation methods to establish EMP samples of specific lengths, widths, and other characteristics such as surface area. Once the samples are created they will be used in toxicity testing, which will occur at the NIOSH Health Effects Laboratory Division (HELD). The associated outputs will be peer-reviewed papers detailing the separation methodologies and results of the toxicity evaluations.

(3) Establish an application of qualitative and quantitative analysis of regulated asbestos and other EMPs for end-of-shift measurement using newly developed and novel techniques for EMP analysis. This aim will focus on creating novel measurement methods to allow accurate measurements of EMP exposure to a miner in near real time or at the end of each work shift, resulting in reduced exposure to EMPs. The associated outputs will be peer-reviewed papers describing technologies that could be used for end-of-shift measurement of EMP.

This project will generate impact by improving knowledge of the fundamental nature of EMP exposure in the mining industry and by establishing a common measurement and analytical protocol to quantify EMP exposure, all of which can be used by mining stakeholders as a basis for improved exposure monitoring and miner protection.

Page last reviewed: 3/8/2019 Page last updated: 3/8/2019