Mining Program Strategic Plan, 2019-2023 - Strategic Goal 1: Reduce mine workers' risk of occupational illnesses

Mining Program Strategic Plan

Mining Program Strategic Goals Overview

Strategic Goal 1: Reduce mine workers' risk of occupational illnesses

The mining environment may expose miners to mineral, chemical, and physical hazards. Mineral hazards include exposure to airborne elongate mineral particles that may cause asbestosis, lung cancer, and mesothelioma. Exposure to respirable coal and crystalline silica dust may cause coal workers’ pneumoconiosis (CWP) and silicosis, and both crystalline silica and diesel emissions are classified as carcinogens by the International Agency for Research on Cancer (IARC). In relation to chemical hazards, one of the primary hazards experienced by mine workers results from exposure to diesel emissions in confined spaces with inadequate levels of ventilation, which may lead to lung cancer and cardiovascular health problems. Physical hazards include exposure to high levels of noise, heat, and tasks that require forceful exertions, awkward postures, and repetition rates that pose a risk of musculoskeletal disorders. Over half of the mining workforce has experienced one symptom of heat stress or strain in the previous year, and nearly one-third reported four or more symptoms. This problem has become exacerbated by mining into deeper, hotter environments. Finally, extraction of ore in confined spaces with high-horsepower equipment results in miners having a higher level of hearing loss than workers in any other major industry.

Below, in the boxes to support Strategic Goal 1, each intermediate goal is followed a series of activity goals—activities that move the research through the NIOSH research to practice (r2p) continuum—then a table, then an analysis of burden, need, and impact. The table lists the health and safety concerns; describes the research focus areas; identifies the mining sectors or worker populations affected; defines the research type used to address the concerns, and links to key Mining Program research projects that target solutions.

Click on a box representing the intermediate goal to expand or collapse it.

Activity Goal 1.1.1: (Basic/Etiologic Research) Conduct studies to improve measurement of exposures to elongate mineral particles, diesel emissions, respirable crystalline silica and other dusts, and to better understand the risks for respiratory diseases among mine workers.

Activity Goal 1.1.2: (Intervention Research) Conduct studies to develop and assess the effectiveness of interventions and technologies to prevent overexposure to elongate mineral particles, diesel emissions, respirable crystalline silica, and other hazardous dusts to reduce respiratory diseases among mine workers.

Activity Goal 1.1.3: (Translation Research) Conduct studies to improve the adoption of control interventions and technologies to reduce overexposure to hazardous airborne contaminants in the mining environment.

Activity Goal 1.1.4: (Intervention Research) Conduct studies to assess the effectiveness of foamed or slurried rock dust to minimize respirable dust generation during applications of rock dust in underground coal mines.

Activity Goal 1.1.5: (Basic/Etiologic Research) Conduct studies to assess health effects of exposure to treated and untreated rock dusts.

Activity Goal 1.1.6: (Intervention Research) Conduct studies to develop interventions that reduce dust (including respirable crystalline silica) at transfer points of ore haulage conveyors.

Health and Safety Concern Research Focus Area Mining Sector/
Worker Population
Research Type Related Project Research
Asbestos-related diseases Exposure to elongate mineral particles Industrial minerals; metal; stone, sand, and gravel Intervention Basic/Etiologic Mineral reference materials
Respirable dust-related diseases Organizational and worker practices Metal/nonmetal; stone, sand, and gravel; coal; underground mining

Intervention
Basic/Etiologic
Translation

Health and safety management
(ended in 2019)

Health and safety indicators
(added in 2019)

Silica-related diseases Exposure to crystalline silica Coal; industrial minerals; metal; stone, sand, and gravel Intervention

Exposure monitoring
(ended in 2019)

Dust sensing and control
(added in 2019)

Conveyor system safety
(added in 2019)

COPD; lung cancer; cardiovascular disease Exposure to diesel aerosols and gases Underground coal; industrial minerals; metal; stone, sand, and gravel Basic/Etiologic
Intervention

Diesel aerosols

Diesel particulate matter

Exposure monitoring
(added in 2019)

Coal workers' pneumoconiosis; chronic obstructive pulmonary disease; diffuse fibrosis Exposure to coal respirable dust Coal Intervention
Translation

Respirable dust
(ended in 2019)

Lung irritation Exposure to rock dust Underground coal Intervention Treated rock dust
Silica-related diseases Exposure to respirable crystalline silica and respirable coal dust Underground coal; surface coal

Basic/Etiologic
Intervention
Translation

Silica dust control
(added in 2019)
Burden

Extracting and processing mined materials can result in overexposures to several hazardous airborne contaminants, including elongate mineral particles, coal dust, crystalline silica dust, and diesel exhaust. Analysis of publicly available MSHA compliance data demonstrates overexposures to these airborne contaminants at rates as high as 27%. Overexposure to respirable coal dust can lead to coal workers’ pneumoconiosis (CWP), and exposure to respirable silica dust can lead to silicosis—both irreversible, disabling, and potentially fatal lung diseases. From 1970 through 2015, CWP caused or contributed to the deaths of over 74,000 miners, with over $46 billion paid to compensate them and their families. Recent investigations show that progressive massive fibrosis (PMF), the most severe form of CWP, occurs at rates three times higher than any previously reported levels, and researchers believe that crystalline silica exposure may have contributed to these PMF cases. Exposure to diesel exhaust can affect both respiration and circulation. The International Agency for Research on Cancer (IARC) classifies both diesel engine exhaust and crystalline silica as carcinogenic to humans. Miners suffer from higher rates of asbestosis, lung cancer, and mesothelioma than other workers. In 2007, a mesothelioma cluster of 58 cases was found in 72,000 former taconite miners who worked in the iron range in Minnesota, even though the expected occupational mesothelioma rate is much lower at 1 per 200,000 workers. This higher rate was attributed to exposure to elongate mineral particles associated with the taconite.

Need

Miners experience incidences of respiratory illness and disease that are much higher than the general population, and the standards for exposures to airborne hazards continue to be lowered based on new medical evidence. To that end, a need exists to advance the ways in which health data are being collected and used to prevent exposures. Most recently, the 2016 reduction of the respirable coal mine dust standard from 2.0 to 1.5 mg/m3 created a heightened need for effective controls. To address these needs, the NIOSH Mining Program continues to develop more effective methods to monitor and control hazardous airborne contaminants in mines. In developing such methods, it is critical to effectively identify and use leading indicators within health programs and interventions, as expressed in a recent study published in BMC Health Services Research. NIOSH is uniquely qualified to conduct this research due to its state-of-the-art laboratories for development and testing of dust controls, including full-scale longwall and continuous mining galleries where dust can be generated and measured without putting workers at risk. For diesel-powered equipment, the need is to reduce hazardous emissions from older engines being used in mines. NIOSH has recognized the need to focus on leading indicators in occupational health and safety with a posting on NIOSH’s science blog. NIOSH has extensive laboratories for developing and testing diesel controls, and these facilities are served by a dedicated team with two decades of experience and worldwide recognition for their diesel expertise.

Impact

NIOSH has developed technologies including monitoring and measuring devices and improved control methods to reduce exposure to respirable coal dust, crystalline silica, diesel particulate matter, and elongate mineral particles. These technologies include the PDM 3700, a real-time respirable coal dust monitor commercialized by Thermo Fisher Scientific and required for MSHA compliance sampling; the Airtec, a real-time diesel particulate monitor commercialized by FLIR; and the Helmet-CAM and EVADE software monitoring technology that merges recorded video of worker activities and personal exposure data to identify sources of overexposure. An end-of-shift crystalline silica monitoring technique that is in the final stages of development enables mines to perform silica analysis onsite and in near real-time. This technique replaces the traditional laboratory analysis method that required mines to wait weeks for the results. Current research related to respirable coal mine dust exposures addresses over 60% of the overexposures experienced by coal miners. NIOSH is establishing a repository of characterized elongate mineral particles samples to support toxicology research and developing monitoring technologies to provide real-time data that can be used to prevent overexposures from occurring. NIOSH is addressing DPM exposure by researching retrofitted diesel exhaust technology to help companies prepare for full integration of Tier IV EPA-rated low-emission engines into mines.

Top of Page

Activity Goal 1.2.1: (Translation Research) Conduct studies to remediate barriers to full implementation of hearing conservation programs designed to reduce noise-induced hearing loss among mine workers.

Activity Goal 1.2.2: (Intervention Research) Conduct studies to develop and assess the effectiveness of noise controls for reducing noise exposure from mining equipment.

Health and Safety Concern Research Focus Area Mining Sector/
Worker Population
Research Type Related Project Research
Noise-induced hearing loss Exposure to occupational noise Surface stone, sand, and gravel; equipment operators Translation Hearing conservation
Burden

Mining has a higher prevalence of hearing loss than any other major industry. A NIOSH analysis of over 1 million audiograms from 2000 to 2008 showed that 27% of miners had a material hearing impairment versus 18% for all industries. Mining has the highest prevalence of noise overexposure (76%) according to a NIOSH analysis of the 1999–2004 National Health and Nutrition Examination Survey (NHANES). Common equipment used in mines, such as continuous mining machines, rock drills, and roof bolting machines, generate sound levels over 100 decibels, which can lead to hazardous exposures within minutes. Companies implement hearing conservation programs (HCPs) to address these issues; however, lack of expertise or funding may leave some HCP components under-performing.  There are currently no requirements for mine equipment manufacturers to produce quieter equipment or state the noise levels of their equipment. Therefore, the burden is with the end user to either reduce equipment noise levels by installing aftermarket noise controls or to limit operator exposure. Based on NIOSH project research, about 50% of jumbo drill machines used in the United States do not have cabs; therefore, operators are directly exposed to the noise generated by the machine. Although hearing loss does not typically result in loss of life, it greatly impacts the quality of the worker’s life, both on and off the job.

Need

NIOSH Mining Program research specifically addresses a knowledge gap in noise overexposure that affects miners. A process of objective data analysis and subjective interviewing is needed to identify the underlying issues to full, effective implementation of HCPs and in turn to provide solutions to improve those areas. Some inspectors, specialists, and MSHA Technical Support conduct field engineering studies to identify sound levels and noise sources, and although MSHA collects noise exposure data via dosimetry for compliance determination, MSHA does not evaluate the actual noise levels produced by the machinery during operating conditions as part of its routine exposure compliance sampling. NIOSH fills that gap by conducting laboratory and field research to determine overall sound levels and identify primary noise-generating components of machinery, and in turn developing suitable noise control solutions. The NIOSH Mining Program is ideally suited to develop these solutions, with a large hemi-anechoic chamber and a National Voluntary Laboratory Accreditation Program (NVLAP)-accredited reverberation chamber, large enough to test working mining equipment. The hemi-anechoic chamber is used in conjunction with an 84-microphone beamforming array to identify the physical location and the frequency content of dominant noise sources in mining equipment. This essential information helps NIOSH to develop effective noise controls that directly address the dominant noise sources. The reverberation chamber is used to obtain accurate measurements of the sound power radiated by a mining machine before and after the newly developed noise controls are installed. This allows NIOSH to evaluate the performance, in terms of noise reduction, of the developed noise controls. These state-of-the-art facilities , instrumentation and software, relationships with original equipment manufacturers, and expertise to develop engineering noise controls for mining equipment, uniquely position NIOSH as a leader in mining noise control development and testing.

Impact

NIOSH noise control technologies address hazardous noise at the source. NIOSH partnerships with manufacturers allow the Mining Program to act as a close collaborator to develop and evaluate the feasibility of noise control properties, while allowing manufacturers to market and distribute the end products. Joy Global has manufactured a longwall shearer drum to include design modifications and engineering developed by NIOSH. Other NIOSH-developed commercially available noise control technologies include coated flight bar conveyor chains and dual sprocket conveyor chains, to reduce continuous miner conveyor noise levels, and drill bit isolators, to reduce noise exposure during underground coal roof bolt drilling. These controls, when installed, used, and maintained properly, can reduce the overall daily noise doses of the machine operator by 30–50%, as shown by the collective findings from three NIOSH studies on coated flight bars for a continuous mining machine (CMM), a dual sprocket chain on a CMM, and noise controls for roof bolting machines. Future research will expand on the quiet-by-design approach through partnerships with manufacturers to design controls into machines during production. Current NIOSH research is also identifying primary noise sources and noise-hazardous areas at surface mining facilities and addressing actual and perceived barriers to full implementation of HCPs at surface stone, sand, and gravel mines. The results will demonstrate a broad context fit across the surface mining industry, with potential application to similar machines and tasks in construction and other heavy industries.

 Top of Page

Activity Goal 1.3.1: (Basic/Etiologic Research and Intervention Research) Conduct studies to determine and reduce the occupational risk factors associated with heat illness in the mining industry.

Health and Safety Concern Research Focus Area Mining Sector/
Worker Population
Research Type Related Project Research
Heat illness Detecting and
preventing heat stress in mine workers
All Basic/Etiologic
Intervention
Translation

Heat strain
Burden

Heat stress is a challenge in many industries, including mining, and can lead to heat strain among workers. A total of 139 heat exposure/illness incidents among metal and nonmetal miners were reported to MSHA during 2006–2015. However, heat illness incidents among miners are likely underreported, especially if they do not lead to lost work days. Many symptoms, such as difficulty concentrating, poor motor control, and chronic fatigue that could be attributable to heat strain are likely ignored, with workers not recognizing the causal relationship. As one example of the scope of the problem, in one study of heat strain prevalence, 56% of miners reported at least one symptom of heat strain or heat stroke while working during the previous year, and 31% had experienced four or more symptoms in the previous year. Mine rescue operations in the United States resulted in a heat-related double fatality in October 2002. With the coolant canisters of their breathing apparatus not properly outfitted with gel packs, two members of a team exploring an abandoned mine slope in Nevada were fatally overcome by heat exhaustion. As underground mines expand into deeper, hotter environments, and surface mines continue to operate in hot climates, heat stress and strain among miners are likely to increase.

Need

The extent and magnitude of heat strain among miners have not been well characterized, nor have the environmental and personal risk factors in relation to effects such as cognitive function and performance declines. Heat stress refers to the total heat load placed on the body from external environmental sources and from physical exertion, whereas heat strain refers to the physical strain the body experiences as a result of heat stress. In addition to immediate effects that can increase the risk of injury (e.g., impaired reaction time, sweaty palms, etc.), heat strain can lead to adverse heat-related conditions of varying severity, such as the development of rashes, syncope, heat exhaustion, and heat stroke, which can be fatal or induce long-term impairment. Given the Mining Program’s established history of collaborating with mining companies, and expertise in medicine, industrial hygiene, and epidemiology, NIOSH is well positioned to define issues that accurately describe the incidence of heat-related illnesses as well as target and conduct research that may reduce the potential for such illnesses and can be translated to industry. This research will analyze the contributing factors and the symptoms experienced by heat-exposed miners in order to identify, develop, and evaluate targeted solutions and guidance.

Impact

A better understanding of the environmental, physiologic, and cognitive attributes related to individual heat strain will inform the NIOSH Mining Program’s guidance and development of mitigation strategies, as well as evaluations of their effectiveness. Advancing knowledge in this field will help to train miners and supervisors on effective heat stress monitoring techniques and heat illness prevention and will inform policies on work organization to prevent heat illness. As one example, NIOSH project research to establish methods to evaluate the cognitive effects and predictive indicators of heat strain can assist workers in identifying imminent decreases in mental performance and increases in risk of illness or injury among themselves as well as their peers. Recent Mining Program publications such as a series of heat stress fact sheets offer practical advice that workers can use to stay safe while performing their duties in hot environments. Collectively, information on heat stress will fill an important gap in heat research and can help to direct improvements to work/rest cycles, hydration frequency, and job tasks to prevent heat illness, thus helping to maintain worker performance and mining production.

Top of Page

Activity Goal 1.4.1: (Intervention Research) Conduct studies to develop and assess the effectiveness of interventions to reduce musculoskeletal disorders among mine workers.

Activity Goal 1.4.2: (Intervention Research) Conduct studies to understand barriers and improve the adoption and implementation of evidence-based interventions, design recommendations, and work practices to reduce musculoskeletal disorders at mine sites.

Health and Safety Concern Research Focus Area Mining Sector/
Worker Population
Research Type Related Project Research
Cumulative and traumatic injury from slips, trips, and falls Ladders and walkways; boot wear Surface stone, sand, and gravel; mineral processing plants; coal preparation plants Intervention Slips, trips, and falls
(ended in 2019)
Musculoskeletal disorders Hazard recognition;
shoulder overexertion injuries, hand and finger injuries, manual materials handling
Surface stone, sand, and gravel;
all
Intervention

Hazard recognition
(ended in 2019)

Manual materials handling
(added in 2019)

Burden

Of all nonfatal occupational injuries and illnesses reported to MSHA between 2006 and 2015, just over one-third (34%) were musculoskeletal disorders (MSDs). The median number of days lost, which is the sum of days lost from work and the number of days with restricted work activity, was 19 for all reported MSD cases. Musculoskeletal disorders have direct costs (medical plus compensation payouts) and indirect costs (lost wages, fringe benefit losses, training, hiring, and disruption costs, etc.). Older workers, and those with more mining experience, show more days lost from work work—defined in the article cited above as the sum of days lost from work and days of restricted work activity—as compared to their younger, or less experienced, counterparts, who show a higher frequency of injury. Further, having a past MSD places a worker at a higher risk for developing a future injury, and re-injury rates can be especially high in some jobs, leading to the loss of a worker from his or her specific occupation. MSDs affect the quality of life of workers, limiting their physical capabilities, vitality, and even negatively impacting their mental health.

Need

From an ergonomics standpoint, mining tasks that require forceful exertions, awkward postures, and repetition rates that pose a risk of musculoskeletal disorders are ubiquitous, and these tasks are present across mining commodities. Unusual postures and restricted spaces often exacerbate the exposure and risk. The NIOSH Mining Program is well-positioned to address these problems and has been a significant contributor globally to mining ergonomics research over the past two decades. NIOSH’s research team of biomechanists, ergonomists, and engineers uses an interdisciplinary focus to develop practical solutions to mining industry problems. In addition to work physiology, strength assessment, and motion analysis laboratories, NIOSH’s unique Human Performance Research Mine can be configured to mimic various underground mining scenarios, including operation of actual mining equipment, with state-of-the-art data acquisition capabilities that measure human performance parameters during simulated work. This research mine allows NIOSH to conduct carefully controlled yet highly relevant studies that are not feasible in typical mining environments due to often harsh environmental conditions. NIOSH researchers also maintain working relationships with mine operators that facilitate the access needed to conduct field assessments on site, and to determine the necessary characteristics for laboratory simulations. Working directly with mine operators helps NIOSH to fill knowledge gaps and ensure that the work is timely and targeted to reducing MSD risk factors.

Impact

NIOSH’s proven history of helping mines address ergonomics issues includes the publication Ergonomics and Risk Factor Awareness Training for Miners, which has been used extensively to educate miners about how their bodies’ age and steps they can take to protect their musculoskeletal health. More recently, ErgoMine, an Android application created by NIOSH, has delivered over 2,200 recommendations to miners in the first year after being published. ErgoMine 2, currently under development, will be available on Android and Apple platforms and is planned for release in 2020. ErgoMine provides customized recommendations for addressing observed ergonomics and safety issues detected while answering a series of easy-to-understand questions or inputting weight and distance measurements. Future impact will be made in the area of slips, trips, and falls (STFs) through research to develop tools to identify, report, and remediate STF hazards in the workplace. These impacts will be achieved through significant field studies and interaction with miners, laboratory studies, and continued surveillance of injury and illness data.

Top of Page

Activity Goal 1.5.1: (Surveillance Research) Conduct analyses of secondary data sources to determine the occupational health issues affecting the mining industry.

Activity Goal 1.5.2: (Intervention Research) Develop human-centric lighting interventions to address occupational health issues associated with shift worker circadian disruption.

Health and Safety Concern Research Focus Area Mining Sector/
Worker Population
Research Type Related Project Research
Chronic disease Worker health All Surveillance

Miner health evidence-based framework
(ended in 2018)

Chronic disease Worker health Underground coal and metal mines Intervention Circadian disruption
(added in 2019)
Chronic disease Leading health and safety indicators All Surveillance Health and safety indicators
(added in 2019)
Burden

There is limited information about the current health status of the mining population in the United States, and the information that is available varies across the mining sub-sectors (e.g., coal, metal/nonmetal [M/NM], stone/sand/gravel). No comprehensive or narrowly focused health surveillance systems exist for this population. Approximately 80 different commodity types are mined and processed in the United States. Because these commodities are derived from a broad range of rock types that may be compositionally heterogeneous, they pose a range of exposure hazards (inhalation, ingestion, contact, etc.). Despite research-based advances in knowledge of health problems such as black lung and hearing loss, gaps exist in empirical understanding on the health effects of acute and chronic exposures to hazards common in mining, such as airborne contaminants, noise, heat, and repetitive stresses. Greater knowledge is critical to addressing the morbidity and mortality of chronic diseases among miners. Further, the mining industry often uses shiftwork to ensure a productive working mine around-the-clock. The top two mining sub-sectors using shiftwork are coal mines (68.3%) and metal mines (64.7%). According to a recent study, the health risks related to shiftwork include type 2 diabetes, obesity, heart disease, stroke, and cancer.

Need

Surveillance of worker health remains fundamental to the mission of the NIOSH Mining Program. Despite clear programmatic expertise in occupational health surveillance, no surveillance efforts are specifically dedicated to the systematic examination of injury and illness burden within the mining industry. With expertise in mining engineering, industrial hygiene, and epidemiology, and given NIOSH’s proven history in collaborating with industry, NIOSH is uniquely positioned to lead and coordinate the necessary efforts for obtaining, managing, and analyzing several data sources that will aid in describing what is currently known about the health of miners. Initial data sources planned for analysis include the Wyoming Miners’ Hospital, Miners’ Colfax Medical Center, Kennecott Utah Copper, MSHA, the National Health Interview Survey (NHIS), and the Behavioral Risk Factor Surveillance System (BRFSS) as well as cumulative analyses of big data efforts being led by NIOSH throughout the industry. Health data are collected daily by various members of mine management and, with so much data available, NIOSH has the capability to take advantage of advanced machine-learning statistics, improved infrastructures for managing big data, and helping mines adapt on a continual basis in response to unforeseen risks. Therefore, a methodology for regular and systematic review of available health-related data sources must be instituted in order to establish baseline measures and build a more robust surveillance program that can evaluate the efficacy and effectiveness of implemented health and safety strategies. NIOSH researchers have a strong rapport with companies and know that future guidance must come to them in a more tangible way to help measure progress and encourage longevity of health surveillance. As one example, human-centric lighting interventions are an effective means of addressing circadian disruption from shiftwork given that circadian rhythms depend upon the natural light and dark cycles. NIOSH has distinct advantages and unique resources for conducting lighting intervention research. Mine lighting research involving the testing of human subjects has been conducted for at least a decade; thus, researchers have extensive experience with mining equipment, mine lighting, human subject protocols, and the human factors of lighting. NIOSH also has unique resources that include a lighting laboratory and highly specialized photometry instrumentation.

Impact

The NIOSH Mining Program has a long history of providing analyzable data files and summary statistics for the mining industry for public use, including MSHA data files and documentation. Building on this resource, the proposed work will help to establish a foundation for a surveillance program called the Miner Health Program, which will identify workers and collaborators in developing health and safety initiatives and will routinely monitor and assess miner health. A structure and procedure for securing and analyzing health-related data will be instituted, thus enabling a systematic assessment of what is currently known about miner well-being and the potential hazards that may contribute to adverse health effects. Among several outcomes, these assessment methods will aid in identifying specific knowledge gaps in miner health and in prioritizing health issues and hazards that are ready for intervention or require new primary and secondary data collection to improve risk estimates. The primary human-centric lighting outcomes include a reduction in circadian disruption and new knowledge about human-centric lighting efficacy in mining applications.

 Top of Page

Page last reviewed: 11/10/2019 Page last updated: 1/6/2020