Mining Project: Monitoring and Control of Airborne Toxic Substances in Mining
The objectives of this project were (1) to advance the assessment and monitoring of exposure to respirable aerosols in mining, namely crystalline silica, coal dust, and diesel particulate matter, through the development of timely, accurate, and site-specific monitoring technologies and strategies; and (2) to evaluate and implement advanced and emerging diesel emissions control technologies.
NIOSH visited a metal mine operation in March 2016.
Workers in the mine environment can be exposed to high levels of toxic aerosols, including crystalline silica and diesel particulate matter. Inhalation of respirable crystalline silica can cause silicosis, an incurable and potentially fatal lung fibrosis. One of the most significant hurdles in controlling exposure to crystalline silica is the inability to rapidly monitor the exposure. To address this problem, one focus of this project was to develop field-based silica exposure monitoring solutions. These solutions, namely end-of-shift (EoS) or in-shift, will empower mine operators to avoid or mitigate high crystalline silica levels in the mine environment.
In 2012, the International Agency for Research on Cancer (IARC) labeled diesel exhaust as a human carcinogen, and a recently published NIOSH study reported that heavy exposure of miners to diesel exhaust increases the risk of death from lung cancer. Therefore, another focus of this project was to evaluate complex diesel engine exhaust after-treatment systems designed for simultaneous control of both nitrogen oxides (NOX)—a component of diesel exhaust—and diesel particulate matter (DPM) emissions for application in mine environments. These Environmental Protection Agency Tier 4 technologies are rapidly evolving but are not optimized for underground mining. To protect worker health, research is needed before widespread implementation of these engines in the mining environment.
NIOSH dust chamber ready to test dust from an iron mine.
This work was carried out by way of three research aims:
- Assess the performance and implementation of end-of-shift or in-shift solutions for monitoring crystalline silica in mining.
The goal was to recommend the implementation of promising solutions to the mining industry. The team did consider both commercially available technologies and strategies and the design of innovative techniques. A commercially available candidate, Fourier transform infrared spectroscopy (FTIR) spectroscopy, was optimized and revised for the targeted needs of specific mining environments. In some instances, researchers pursued the integration of the identified solutions with monitoring devices and technologies currently used in mining.
- Evaluate the suitability of advanced and emerging medium- and heavy-duty diesel engine emissions control technologies for mining applications.
Several currently available advanced diesel particulate matter control strategies and technologies were evaluated in the field. The contributions of various diesel-powered vehicles to diesel aerosol concentration during longwall move operations in an underground nonmetal mine were assessed over several shifts. The individual contribution of various vehicles and effects of various control strategies including a sintered metal filtration system, advanced engines, and environmental enclosures with filtration systems were evaluated in an underground operation using isolated zone methodology. The advanced retrofit-type exhaust aftertreatment devices, optimized for underground mining operations, were thoroughly evaluated at the NIOSH Pittsburgh Mining Research Division diesel laboratory. It was learned that implementation of advanced diesel technologies, alternative fuels, and improvements in ventilation can result in measurable reductions in exposure of underground miners to diesel particulate matter.
- Assess the performance of the DPM sampler currently used in M/NM mines.
The project tested the performance and limitation of the DPM samplers—an impactor currently used by the Mine Safety and Health Administration (MSHA) and a novel sharp-cut cyclone—in a limestone mine. The testing was done in collaboration with Virginia Tech University. The data is being analyzed to determine the direction of future research.
The Tier 4 diesel engine that will soon be tested in the NIOSH diesel laboratory.
In addition, NIOSH’s statutory obligation to approve new and modified coal mine dust sampling devices under 30 CFR 74 was fulfilled in the frame of this project.
William Archer - Electronics Technician
Teresa Barone - Associate Service Fellow
Aleksandar Bugarski - Mechanical Engineer
Emanuele Cauda - Senior Service Fellow
Lauren Chubb - Physical Scientist
Jon Hummer - Engineering Technician
Jason Pampena - Associate Fellow
Donald Tuchman - Industrial Hygienist
Shawn Vanderslice - Engineering Technician
YouTube video - Faces of NIOSH - on the new field-based approach to silica monitoring for mines
- A CART Technique to Adjust Production from Longwall Coal Operations under Ventilation Constraints
- Diesel Exhaust Aerosol, Review of Measurement Technology
- Evaluation of Sequential Extraction Procedures for Soluble and Insoluble Hexavalent Chromium Compounds in Workplace Air Samples
- An In-Situ Diffusion Parameter for the Pittsburgh and Pocahontas No. 3 Coalbeds
- Instrumentation for Diesel Particulate Matter Emissions Research
- Morphological and Elemental Classification of Freshly Emitted Soot Particles and Atmospheric Ultrafine Particles using the TEM/EDS
- Real-time Neural Network Application to Mine Fire - Nuisance Emissions Discrimination
- Ringelmann Smoke Chart
- Sonic Anemometer Airflow Monitoring Technique for Use in Underground Mines
- Use of Vacutainers for Collection of Mine Atmosphere Samples