Mining Program Strategic Plan, 2019-2024

Introduction

The National Institute for Occupational Safety and Health (NIOSH) is an institute within the Centers for Disease Control and Prevention (CDC) under the Department of Health and Human Services (HHS) and is responsible for conducting research, providing new scientific knowledge, making recommendations, and delivering practical solutions to prevent worker injury and illness. The NIOSH Mining Program provides health and safety research and science-based interventions for the mining workforce. The Mining Program is under the direction of the Office of Mine Safety and Health Research (OMSHR) and includes both the Spokane Mining Research Division (SMRD) in Spokane, Washington, and the Pittsburgh Mining Research Division (PMRD) in Pittsburgh, Pennsylvania.

The NIOSH Mining Program conducts research to eliminate occupational diseases, injuries, and fatalities from the mining workplace. Our goal is to ensure that our research portfolio responds to the greatest needs of the industry, that our work is of the highest quality, and that our limited resources will have the greatest impact. We provide solutions for miners working in the five major mining subsectors: metals, industrial minerals, crushed stone, coal, and sand and gravel (see Appendix B). Our work extends to surface and underground operations, along with associated plants, mills, shops, and offices.

Purpose of the Strategic Plan

This Strategic Plan serves as a roadmap and forms the research foundation for the NIOSH Mining Program. It informs our research project planning, sets the priorities and goals for the upcoming years, and ensures that our work will be relevant and impactful. We initially developed the NIOSH Mining Program research strategy in 2004 to focus mining research and prevention activities on the areas of greatest need, as articulated by our stakeholders and supported by surveillance data. Partnerships and collaborations continue to be critical to maximizing the impact of our research. Additionally, we are incorporating evaluation methods within our research to strengthen project planning, tracking of outcomes, and documentation of impact in relation to our project aims as well as strategic goals.

Since the implementation of the original 2004 Plan, the face of mining health and safety has changed due to: (1) a series of disasters that resulted in passage of the Mine Improvement and New Emergency Response Act (MINER Act) of 2006, which drove new technological development; (2) a trend toward mining in more complex geological conditions; (3) a push toward deeper mines; (4) the continuing introduction of automation and new technologies in mining and the sociotechnical factors these technologies bring; (5) the contraction of the U.S. coal industry and the recent growth of the aggregates industry; and (6) changes in the demographics of the mining workforce, with a trend toward younger, less experienced workers and more contractors. In light of these and other changes, this updated Plan sets new research priorities based on Burden, Need, and Impact (BNI), stakeholder input, and the regulatory agenda including rulemaking by the Mine Safety and Health Administration (MSHA). The Plan is meant to clearly communicate, both internally and externally, what the NIOSH Mining Program is doing, why we are doing it, and how our activities contribute to our success.

Setting Research Priorities

Setting research priorities is one of our biggest and most important challenges. Our goal is to ensure that the priority setting process is broad-based, inclusive, unbiased, transparent, and data driven. The ability to evaluate progress and measure the success of these priorities is critical to the relevance and impact of the Mining Program. The process must also be responsive to changes in industry needs and interests. We draw on a number of different sources for input into the process and they are described below.

Burden, Need, and Impact

NIOSH uses Burden, Need, and Impact (BNI) to identify and define research priorities (see box). BNI is an objective framework that structures research planning to ensure we do the most important work to protect the workforce and identify research priorities to guide the investment of limited resources in a clear and transparent manner.

The NIOSH Mining Program establishes burden and need through surveillance data, statistical analysis, stakeholder input, and risk analysis. Surveillance data show how workers are being fatally injured, injured, or impaired. Our stakeholders identify their needs, and we communicate with our stakeholders regularly to better understand those needs. We use risk analysis to assess low-probability, high-impact events such as mine explosions.

Committee and Partnership Engagement

Our stakeholders are the end users of our research and therefore our research is largely driven by their needs. Our stakeholders are diverse (see sidebar below) and each group has unique perspectives and interests when it comes to mine worker health and safety. NIOSH relies on several mechanisms for gathering input.

One mechanism involves convening partnerships to bring diverse perspectives to the table around technically complex topics. This model for collaboration has proven to be highly effective. Currently there are six active partnerships: Breathing Air Supply Partnership, Respirable Mine Dust Partnership, Diesel Health Effects Partnership, Rock Dust Partnership, Automation and Emerging Technologies Partnership, and the newest, the Miner Health Partnership (NIOSH 2020j). These partnerships are comprised of representatives from equipment manufacturers, academia, mining companies, labor unions, trade associations, and government agencies. Our partnerships web page provides additional information about NIOSH Mining’s partnership activities.

In addition to partnerships, the NIOSH Mining Program receives advice from the Mine Safety and Health Research Advisory Committee (MSHRAC), which is a Federal Advisory Committee initially established under the Federal Coal Mine Health and Safety Act of 1969 (Public Law 91-173) and is comprised of representatives from our major stakeholder groups. MSHRAC provides advice on mine safety research and serves as a productive forum for information exchange. To ensure that the advice from the committee is objective and available to the public, MSHRAC utilizes the rules for engagement under the Federal Advisory Committee Act (FACA) [GSA 2017].

An additional effort to advance communication and collaboration across the mining health and safety community includes the NIOSH-facilitated National Occupational Research Agenda (NORA) Mining Sector Council. This broad, non-advisory Council comprises representatives across the occupational health and safety spectrum, including public- and private-sector researchers, professionals, consultants, practitioners, and manufacturers. The Council works to identify the most salient needs of this large and diverse global sector, facilitate the most important research, understand the most effective intervention strategies, and learn how to implement those strategies to achieve sustained improvements in workplace practice. NORA runs in ten-year cycles and is now in its third decade. During its second decade, the Mining Sector Council developed the National Mining Agenda for Occupational Safety and Health Research and Practice in the U.S. Mining Sector (the Agenda).

The Agenda is made up of 8 objectives and 62 sub-objectives and captures the breadth of current occupational health and safety challenges facing the U.S. mining industry. During its third decade, the Council is focusing on prioritizing the objectives and sub-objectives of the Agenda. These objectives are for the good of the nation and all of its research and development entities, whether government, higher education, or industry related. The Mining Program goals support each of the NORA Mining Sector Agenda objectives and articulate NIOSH’s contribution. The NORA Mining Sector Agenda objectives support each of the strategic goals of the Mining Program. An update to the Agenda based on input from the Council members is currently underway and expected to be finalized in late 2022.

In summary, the NORA Mining Sector Agenda was developed and implemented through the NORA Mining Sector Council and is guidance for the nation as a whole, while the NIOSH Mining Program Strategic Plan is specific to NIOSH and its capabilities and resources.

Rulemaking

The MSHA rulemaking process can also affect our research priorities. NIOSH and MSHA communicate and collaborate on a regular basis to better serve our common goal of improving mine worker health and safety. One mechanism for communication between our agencies is through a Request for Information (RFI)—one recent example is MSHA's Respirable Silica (Quartz) [MSHA 2019c]. An RFI requests data, comments, and other information from the public relevant to the problem presented. When relevant scientific research is available, the NIOSH Mining Program submits a formal response to the RFI based on our scientific expertise. This comment period is a formal mechanism for the NIOSH Mining Program to participate in the rulemaking process.

Our responses to an RFI help MSHA to determine an appropriate course of action to address a particular health and safety problem or issue. MSHA may choose to enact or develop a rule based on this scientific information. If a rule is pending, we may choose to redirect our research to bring the best science possible to the mining community before the rule is in place or during the rulemaking process. Through this process, we can proactively provide scientific evidence to MSHA for developing and implementing new rules that protect miner health and safety.

Strategic Research Goals

The Mining Program Strategic Plan focuses on two hierarchies of goals: strategic and intermediate goals. We keep our strategic goals purposely broad in scope, maintain them as generally long-standing, and achieve them through the outcomes of the Mining Program research portfolio. Intermediate goals are more specific goals that focus on the research or knowledge gaps that must be addressed in order to meet the strategic goals. Intermediate goals cascade from the strategic goals, and each strategic goal has multiple intermediate goals that will change over time as specific intermediate goals are met.

This Strategic Plan also provides future direction and recommendations for research needed to address impending and trending issues. Internal and external reviews of the Mining Program identify research topics that should be addressed to improve the health and safety of the mining workforce. Reports from recent reviews and feedback include:

• NORA Mining Sector Council Agenda
• NIOSH Mining Program Expert Review
• Haul Truck Research Roadmap (internal report)
• Mine of the Future: Disruptive Technologies that Impact our Future Mine Worker Health & Safety Research Focus (internal report)
• Automation and Emerging Technologies Agenda and workgroup outcomes and presentations
• Summary Report for Interim Peer Review of Field-based Respirable Crystalline Silica Monitoring Approach Project (internal report)
• MSHRAC
• Miner Health Strategic Agenda
• Partnerships discussions
• In some cases, NIOSH may not be the best organization for carrying out this research due to available expertise, resources, or skill sets. However, these recommendations are discussed, prioritized, and considered by the Mining Program when developing the call for project concepts. These recommendations are provided under each Strategic Goal under the Future Directions heading to show the critical path forward to improve mine worker health and safety. When a health and safety issue as described in the Future Directions section becomes more prevalent or defined, it may move forward as a pilot project or as a full project. A description of the activities of current full projects and links to those projects are available under each associated goal.

The NIOSH Mining Program has established three overarching strategic goals for this plan:

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

Strategic Goal 2: Reduce mine workers' risk of traumatic injuries and fatalities.

Strategic Goal 3: Reduce the risk of mine disasters and improve post-disaster survivability of mine workers.

Overview and Guide to Strategic Goals

As an overview of the Mining Program Strategic Plan, 2019–2024, Table 1 represents these three strategic goals, along with their associated intermediate goals (IGs) and related NIOSH goals, in the context of a five-year planning horizon.

Table 1. Mining Program Strategic Plan Overview, 2019-2024*

*On a yearly basis, this Plan will be reviewed and updated to ensure its relevance to the current issues facing the nation's mining workforce.

Intermediate Goals

The NIOSH Mining Program recognizes that we cannot make improvements to occupational safety and health without the assistance of our stakeholders. Therefore, we also establish intermediate goals that are the actions that organizations should take—namely, to use NIOSH research findings and products that will directly contribute to health and safety. It often takes years and the combined effort of multiple research projects to achieve intermediate goals. Based on the standard research project cycle, an average time frame for achieving an intermediate goal is five years.

The intermediate goals defined in this Plan represent relevant problems that the NIOSH Mining Program is committed to solving, and they were selected because they are on the critical path to meeting our strategic goals. Furthermore, they are achievable given our staff, facilities, and funds. In the Strategic Goals, Intermediate Goals and Activity Goals section of this document, the Burden, Need, and Impact for each strategic goal is described, the intermediate goals that contribute the strategic goal as well as the activities that contribute to the intermediate goal are provided. The projects that directly contribute to the activities of the intermediate goal are linked.

Activity Goals

Integrally tied to achieving intermediate goals are activity goals. These are activities that move the research through the NIOSH research to practice (r2p) continuum. The NIOSH Mining Program organizes its research into four categories: (1) basic/etiologic, (2) intervention, (3) translation, and (4) surveillance. These four categories are defined below, as described by the NIOSH Strategic Plan research goals webpage.

• Basic/Etiologic Research: Builds a foundation of scientific knowledge on which to base future interventions. Most laboratory research falls into this category, as well as exposure assessment.
• Intervention Research: Engages in the development, testing, or evaluation of a solution to an occupational safety and health problem or the improvement of an existing intervention. Intervention is a broad term that includes engineering controls, personal protective equipment, training, and fact sheets, and other written materials intended to inform and change behavior, among other occupational safety and health solutions.
• Implementation Research (formerly Translation Research): Discovers strategies to translate research findings and theoretical knowledge to practices or technologies in the workplace. This type of research seeks to understand why available, effective, evidence-based interventions are not being adopted.
• Surveillance Research: Develops new surveillance methods, tools, and analytical techniques.

Activity goals describe which of the four categories will be used to move goals into practical application and are presented in the context of their associated intermediate goals. Each activity goal names the research category, articulates how the problem or gap will be addressed, identifies the targeted health or safety outcome and links the mining program project related to these activities.

Extramural Research Program

In many cases, there are additional research problems that must be addressed outside of the NIOSH Mining Program intramural project portfolio in order to fully meet the strategic goal. Often these problems are addressed through our extramural program and, while our Strategic Plan does not specifically incorporate research being conducted outside of the NIOSH Mining Program, it does provide a strategic framework for extramural partnership through contracts, grants, and interagency agreements.

The extramural research program that was established with the passage of the MINER Act of 2006 provides extramural funding through a contracts and grants program administered by OMSHR. According to the MINER Act [MINER Act 2006], OMSHR has the authority to:

(A) award competitive grants to institutions and private entities to encourage the development and manufacture of mine safety equipment; and

(B) award contracts to educational institutions or private laboratories for the performance of product testing or related work with respect to new mine technology and equipment.

While a small extramural contracts program existed prior to the MINER Act, that program became an integral part of the NIOSH Mining Program after the passage of the MINER Act. The extramural program stands separate from the intramural program but aligns with our strategic goals, with a strong focus toward the MINER Act intent. Similarly, the NIOSH Strategic Plan reflects the intent of the MINER Act by way of service goals, which contribute to the NIOSH mission by providing a service to individuals and organizations outside of NIOSH, support internally to NIOSH staff, or a combination of the two.

The MINER Act Contracts and Grants Program consists of two parts: extramural contracts administered by the Mining Program and grants awarded by the NIOSH Office of Extramural Programs (OEP). Contracts are developed primarily through Broad Agency Announcement (BAA) solicitations aimed at fostering innovative solutions to key health and safety issues; support is also provided to the intramural program through detailed Request for Proposal (RFP) solicitations to supplement intramural research when resources (staff, facilities, expertise) are not available. Interagency Agreements (IAAs) are also used to take advantage of expertise and synergies with ongoing projects at other federal agencies and federally funded research and development centers (FFRDCs).

Collaborations Across Non-Mining Industry Sectors

This Strategic Plan recognizes that the mining industry shares many similarities with the oil and gas and construction industries. By leveraging NIOSH’s broad-based resources to address worker health and safety challenges for all three high-risk industries, we can have a much greater impact on a larger segment of the U.S. workforce. According to the United States Census Bureau Current Population Survey [U.S. Census Bureau 2020], in 2019, there were 11.4 million workers in construction and 99,000 workers in oil and gas. According to MSHA data, including mine operator employees and contractor employees, 296,909 individuals were working in mines in the United States in 2020 [NIOSH 2022]. In addition to a greater impact on worker health and safety, this multisector strategy also significantly increases the market size for manufacturers by considering the marketing of health and safety interventions developed by NIOSH.

Maximizing Research Impact: Interdisciplinary /Multidisciplinary Collaboration (formerly Overarching Research Approaches)

Engaging multiple disciplines and perspectives in the planning, design, conduct, dissemination, and implementation of mining research can further the impact of our research. Specifically, we have expertise in disciplines and approaches that cut across research designed to address the strategic and intermediate goals. These include impact planning and evaluation, human factors, human-centered design, health communications, surveillance and statistics, and training solutions. Our intent is to provide a holistic approach resulting in science-based, viable, and impactful solutions that meet the needs of the mining sector.

Impact Planning and Evaluation

An initiative underway to build into our projects and program is planning for impact of our research with appropriate evaluation to provide science-based evidence that our research and its outputs are making a difference to the health and safety of the mining workforce. Our impact planning and evaluation effort contributes to and follows the NIOSH Evaluation Capacity Building Plan which utilizes contribution analysis as a method to emphasize the importance of NIOSH’s research. The overall goal is to integrate evaluation into project planning and to develop and implement creative and cost-effective mechanisms to demonstrate the relevance and impact of our work. This endeavor moves beyond the translation of our science through publications into deeper impact levels where the collaborative (stakeholder – NIOSH) implementation of research outputs at worksites are adopted and institutionalized to have a science-based impact.

This impact, when measured, can show proof of health and safety value and provide incentive and confidence for similar applications. It requires sound scientific methods be followed to develop applicable solutions, testing solutions in the lab under controlled environments, then tested and implemented at real-world worksites with following up to see evidence of impact and lessons learned. This type of impact planning and evaluation cannot be done without close relationships with stakeholders and regulatory agencies and therefore these relationships are critical to build at the project inception to ensure the full evidence-based result. The level (or depth) of impact needs to follow a cost benefit comparison: are the resources and time spent providing a high level of impact evidence more important than moving resources on to solve the next health and safety issue. This same approach can be applied on a programmatic level (evaluation of multi-related topics) where the program valuation will benefit from project impact planning and evaluation.

Human Factors

Human factors considerations include environmental, organizational and job factors, and human and individual factors which can affect the health and safety of the workplace. These factors are also components of health and safety management systems (HSMS) and safety culture, which are institution-wide approaches to managing and improving health and safety through organizational practices. The Mining Program recognizes the advantages of providing solutions and practices that can be integrated holistically to provide direction to individual research projects and make their solutions compatible with sociotechnical aspects of the workplace. Moreover, the Program investigates the factors that contribute to the overall HSMS effectiveness and communicates these factors in the form of recommendations to health and safety implementers in the mining industry.

Human-centered Design

Successful engineering solutions need to accommodate the capabilities and limitations of their human operators. Often complex systems, such as automated mining systems, tend to integrate components of smaller systems to make larger systems without methodological consideration to building the entire system and managing user risk. To meet these criteria, the Program applies a human-centered design approach across each of the projects that develop and design human-machine-environment system interactions. This involves assessment of the entire system and how the human workers will interact with that system and the cognitive and physical function of the human in the environment, closely connected to the human requirements and considerations of human factors approaches described above. Ideally, we identify potential health and safety issues during the development process and resolve these issues during iterative design and testing phases.

Health Communications

The Mining Program includes a strong health communications function that contributes to impact by communicating the program’s solutions in the most appropriate way to the stakeholders who are in the best position to improve mine worker health and safety. Purposeful communications of products and scientific results relevant to the mining workforce are necessary to reducing injuries and illnesses. The health communications staff initially engages with projects at the proposal and planning stages to ensure that a detailed dissemination plan is in place, performs an audience analysis, then helps to execute that plan during the project’s lifetime, with specific communication products targeting audiences who can take effective safety and health action. We execute and evaluate the dissemination plan through targeted communications, including publications, exhibits, videos, social media, software, and web content—choosing the best mix of communication tools to serve our stakeholders and their health and safety needs.

Surveillance and Statistics

The Mining Program’s surveillance and statistics staff gather analyzable data files and summary statistics, economic analyses, production statistics, and MSHA data on accident, injuries, and illnesses specific to the mining industry. We perform surveillance analyses to identify the sectors, tasks, machinery and equipment, activities, contaminants, and other factors that are responsible for the greatest risk of injury and illness in order to target our research activities most efficiently. We undertake impact analyses based on injury and illness surveillance data from the mining and regulatory industry to determine the effectiveness of our activities in relation to each strategic and intermediate goal. As part of the dissemination plan, we also review products that involve statistics and apply proven statistical analysis techniques to ensure their quality and usability by stakeholders.

Training Solutions

We integrate a training function across the Mining Program to identify solutions that lend themselves to training and are needed to achieve specific health and safety goals. Our training staff works across research projects to identify areas where miners will need training to accommodate new technologies and to implement new advances in health and safety knowledge, skills, and abilities. First, we perform a training analysis to identify whether there is a training component to a successful intervention; then, if a training component is needed, we develop and evaluate that intervention, which could range from instructional manuals to toolbox talks to simulations that can be performed in a safe environment. Training solutions are packaged alongside the Program’s engineering solutions or can serve as standalone packages that demonstrate effective training approaches and techniques. Opportunities often exist to translate or transfer this knowledge to other industries such as construction and oil and gas extraction.

Ongoing Challenges and Emerging Issues

In the last decade we saw mineworkers working in deeper mines where temperature control and ventilation are difficult, mines that are less accessible, challenging geologic conditions and ores that are lower grade. In situ ground stresses increase with depth and can result in geologic instabilities and seismicity, which will likely require more sophisticated ground support to maintain safe workspaces. We saw that economic pressures will require companies to increase their efficiencies to remain competitive and these issues remain. We also saw mine workers commuting longer distances to work, newer inexperienced workers joining the workforce, and mine worker fatigue issues. These challenges and issues can contribute to increased injuries for workers. Understanding the causes behind these injuries and how they can be addressed is critical. Our current program portfolio has since focused significant research addressing these issues with the goal of translating scientific information and providing interventions that will reduce injuries for the mining workforce.

One such ongoing but successful effort is in the area of respirable crystalline silica (RCS) exposure monitoring. This health hazard which leads to illnesses such as silicosis and lung cancer is still a major concern for mine workers, MSHA, and mining companies.  NIOSH has successfully addressed this concern through an end-of-shift RCS monitoring approach for personal exposure evaluations. In a current pilot project, a novel aerosol sampler will enable the development of the first wearable RCS monitor for near-real-time detection.  This capability can save lives by alerting miners to hazardous RCS concentrations and the need for respiratory protection prior to substantial exposures which can cause lung fibrosis.  This will address the current fibrosis resurgence across the US, especially in central Appalachia.

As we look towards the next decade into the future of mining, we continue to acknowledge and address ongoing challenges and emerging issues such as climate change, decarbonization, increased mineral needs, continued increase in oil and gas production, increased implementation of automation and new technologies, electrification, worker mental health and fatigue, respiratory hazards, heat stress and the effects of COVID 19 and infectious diseases among the miner population. The Miner Health Program will keep these health-related issues in the forefront as the challenges faced by the mining workforce continues. While in many cases it would be difficult to address global new topics, we can understand the issues and bring generalizable knowledge, methods, tools and interventions to better identify and anticipate how these issues will affect mine workers and how to proactively abate their possible effects.

It is predicted that climate hazards (increased heat, drought, heavy precipitation) will increase the challenges to mine companies and their workforces. There is expected to be a shift in demands for minerals given the raw material needs for alternative low-carbon energy technologies.  Current predictions state that the production of electric vehicles will necessarily increase the demand for cobalt, lithium and nickel. Electrifying mining equipment, both underground and surface, haul trucks and trolley systems, and the use of hydrogen and fuel cell technologies, are showing increasing use and will no doubt have safety issues for workers who interact in terms of maintenance, storage and use. Our pilot project which addresses the identification and characterization of health hazards, consequences for not identifying and/or mitigating health hazards will take the first step to inform future research to improve mine worker recognition of health hazards. And our pilot project on flame-tube exploration will contribute to basic knowledge to better understand mitigation of accidents and injuries related to explosions and catastrophic events.

Mine companies continue to adopt automation and other emerging technologies to remain competitive and increase efficiencies. Strategies such as monitoring and control systems, big data analytics, artificial intelligence, cybersecurity, automation, interoperability, and wearable and smart sensors are being deployed across the U.S. mining industry and particularly in coal and metal mines. While automation technology may improve worker health and safety by removing workers from hazards, unintended hazards may also be introduced into the workplace. 

Inevitably, as we move towards automated equipment and processes, the interaction between manual and automated systems is another issue. Even fully automated systems require maintenance and will involve humans in those situations. The likelihood of unintended consequences increases with implementation of new technologies. Providing risk assessment tools can help to identify these needs in the design phase. Consideration for workforce acceptance, how jobs/tasks will change and how workforce skillsets will evolve are critical to the well-being and success of the person in the system. Related to automation and new technologies, wireless network performance requirements (latency, radio link reliability, throughput) are needed to understand possible failures (communication failures, cross talking, etc.) and to ensure robust operation in safety critical applications. These requirements will be defined and guidance provided to original equipment manufacturers (OEMs). Understanding the risks and possible solutions for autonomous or semi-autonomous systems is critical to safer implementation. A pilot project addressing real-time risk management and intervention framework for autonomous mining equipment is currently underway and will examine the feasibility of a system that will encourage interoperability across suites of sensors deployable on a large range of vehicles. For a better understanding of the human factors issues related to automation and emerging technologies, a pilot project complementing a BAA funded project aims to identify, understand, and document human factors considerations and expectations when designing, deploying and implementing automation along its continuum as part of the human systems integrated approach for mine worker health and safety. In order to address these emerging issues, we pay careful attention to the trending needs of the mine worker, as represented in the more detailed “Future Directions” subsection within each Strategic Goal below.

Strategic Goals, Intermediate Goals and Activity Goals

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 respirable crystalline silica (RCS) dust may cause coal workers’ pneumoconiosis (CWP) and silicosis, and both RCS 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.

Work and health are inexorably related, and difficult to fully understand and manage when treated as independent of each other. As stated in the 1970 OSH Act, attributes and influences of health are often different from safety, consequently it is necessary to consider managing health differently than how we manage safety. After several progressive conversations and meetings with our mining community partners, the NIOSH Mining Program established the Miner Health Program (MHP), which is a long-term and systematic effort to understand and improve the health and well-being of all miners through focused integration of research, evaluation, and community engagement. The Strategic Agenda of the MHP has established program goals and objectives that are slightly more agile in nature and meant to help inform this Mining Program Strategic Plan on a regular and ongoing basis. More details on the MHP can be found here.

Below, in support of Strategic Goal 1, each intermediate goal is followed by a series of activity goals—as defined earlier in the Plan—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.

Intermediate Goal 1.1: Workplace solutions are adopted to reduce miner overexposure to hazardous airborne dust and diesel contaminants

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 better understand workers' acceptance and use of dust controls and develop interventions to improve use of dust controls and thereby reduce exposures to elongate mineral particulates, diesel emissions, respirable crystalline silica, and other hazardous dusts to reduce respiratory disease among mine workers.

Activity Goal 1.1.3: (Translational Research) Conduct studies to improve the adoption of control interventions and technologies to reduce exposures 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.

Activity Goal 1.1.7: (Surveillance Research) Conduct surveillance research on mining practices to better understand the risks for respiratory disease among mine workers.

Burden

Extracting and processing mined materials can result in overexposures to several hazardous airborne contaminants, including elongate mineral particles, coal dust, respirable crystalline silica dust, and diesel exhaust. Analysis by NIOSH researchers of publicly available MSHA compliance data demonstrates overexposures to these airborne contaminants at rates as high as 27% [MSHA 2020]. Overexposure to respirable coal dust can lead to 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 [CDC 2017], with over $46 billion paid to compensate them and their families [U.S. DOL 2018].

For more than two decades following the enactment of the 1969 Federal Coal Mine Health and Safety Act (Coal Act), amended in 1977, CWP cases in the U.S. declined significantly [Blackley 2016]. However, this trend unexpectedly shifted in the early 2000s, despite established dust exposure limits, dust control methods and technologies, and medical surveillance programs [Cohen 2016]. Since then, the prevalence of CWP, including progressive massive fibrosis (PMF)—a severe form of CWP, has steadily climbed [Blackley 2016].

In recent years, NIOSH has reported on large clusters of PMF in current and former mine workers at local health clinics in both Kentucky (60 mine workers) and Virginia (416 mine workers) [Blackley et al. 2016; Blackley et al. 2018]. Overexposure to mine dusts containing silica cause serious respiratory illness and overexposure to silica in the MNM sector continues to be a problem [Watts and Parker 1995; Watts et al. 2012; Cauda et al. 2013; Weeks and Rose 2006]. Occupational exposure to silica has long been known to be associated with the development of silicosis [Leung et al. 2012], lung cancer [IARC 1997; Straif et al. 2009], and other airway diseases [NIOSH 2002].

Analysis of MSHA health exposure data from the MNM sector collected over the period of 2010 to 2019 shows that of the 23,375 respirable crystalline silica (RCS) samples 10% were over the Permissible Exposure Limit (PEL), and among those overexposed samples, PPE was used in only 946 of the cases. When looking at RCS exposure in terms of job type, the positions of crusher operator, laborer, stone polisher/cutter, bagging operator, cleanup man, and front-end loader operator have the highest level of exposure with 60% of the overexposures being from these occupations [MSHA 2020].

Exposure to diesel exhaust can affect both respiration and circulation. The International Agency for Research on Cancer (IARC) classifies both diesel engine exhaust and respirable crystalline silica as carcinogenic to humans. In recognition of the potential health hazards of exposure to diesel particulate matter (DPM), MSHA reduced allowable DPM concentrations from 400 µg/m³ to 160 µg/m³ in May 2008 (CFR 57.5060(b)(3)). The number of citations given for the DPM standard peaked in 2009 with 42 citations, a year after the law pertaining to DPM limits was in effect. In 2019, there were 18 citations by MSHA related to DPM standards. DPM limits still seem to be a prevalent issue and conforming to standard 57.5060(b)(3) can dictate airflow requirements of the entire underground stone mine. MSHA records show that in the first decade, only about 66% of underground MNM mines were in compliance with the standard (Tomko et al. 2010), although compliance is increasing due to introduction of new-generation diesel engines. Bugarski et al., 2009 indicate that overexposures to DPM were frequent in the mining industry before 2010.

A more recent review of the MSHA personal health samples for total carbon (TC) and elemental carbon (EC) collected from 2010 to 2019 shows that out of a total of 16,499 samples overexposures occurred in around 11% of samples. The highest DPM exposures apply to mucking machine operators, scoop-tram operators, front-end loader LHD operators, drift miner and scaling crews. In terms of number of overexposures for job types blasting crew were worst affected. Out of the total overexposures, blasting crew were overexposed around 23% times followed by front-end loader operator (12%), truck drivers (11%), scaling crew (8%), jumbo drill operators (6%), and mucking machine operators (6%). Around 80% of all overexposures occurred in the active production area [MSHA 2020]. Finally, miners suffer from higher rates of asbestosis, lung cancer, and mesothelioma than other workers. In June 2018, the National Academy of Sciences (NAS) published a consensus study report on the contaminant exposures in underground mines [NAS 2018]. The report stresses the health hazards posed by respirable crystalline silica. 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 [MDH 2007].

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. Despite this evidence, there remain gaps in knowledge about airborne contaminants, worker exposures, and resulting lung disease. As mining practices may have changed over time, an improved understanding of historical trends in geological conditions, operating conditions, and regulatory compliance history is vital to controlling exposure hazards and associated health risks. To that end, an additional 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 [MSHA 2014].

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 [Almost et al. 2018]. 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. Utilization of improved Tier 4 diesel engines and administrative controls can reduce DPM concentrations and help underground mine operators meet the MSHA standards.

However, adopting new diesel technology is not always feasible nor cost-effective for many underground mine operators. Therefore, improved ventilation plays a vital role in helping mine operators meet the new standards and reduce overexposure of contaminants and there is a need for more research in this area. NIOSH has recognized the need to focus on leading indicators in occupational health and safety with a posting on NIOSH’s science blog [Inouye 2016] touting the use and measurement of leading indicators to evaluate trends over time and to improve interventions. To further the identification of necessary leading indicators around dust exposure and control, 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.

Finally, to further the accurate identification of potential exposure to elongate mineral particles during mining, NIOSH’s minerals laboratory has the proper equipment and decades of experience to establish novel methods for elongate mineral particles characterization and monitoring. NIOSH has addressed overexposure to RCS and dust, in general, by conducting research that entailed collecting exposure data and designing appropriate countermeasures. But such data is derived from air filter samples, which must be sent to a lab, and the results are typically not available for days or weeks. There is a need for mine operators to be able to identify sources of silica dust and “hotspots” in the mine, and this is not possible using current methods that depend on sending samples to a laboratory.

In order to evaluate exposures and make modifications to procedures so as to control exposures in the workplace, it is critical that mines are able to measure airborne RCS in real time under field conditions. NIOSH currently has personnel with decades of experience and unique expertise in the collection and quantification of hazardous airborne particulate matter and subsequent exposure assessment. NIOSH researchers have also developed new spectrometric methods for analyzing filter samples of particulate matter [Miller et al. 2012; Hart et al. 2018], which are now being evaluated for the potential to miniaturize for wearability. Additionally, a wide network of motivated and trusted partners in the mining industry has been developed, which will play a key role in transferring any developed technologies into practice.

Impact

NIOSH has developed technologies, including monitoring and measuring devices and improved control methods, to reduce exposure to respirable coal dust, respirable 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 Inc. and required for MSHA compliance sampling; the Airtec, a real-time diesel particulate monitor commercialized by FLIR Systems, Inc. (now licensed by Airflo Dynamics Limited); 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 [NIOSH 2006a; NIOSH 2016b; Noll et al. 2013].

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 [Lee et al. 2017]. In addition to identifying potential trends in exposures, current research related to respirable coal mine dust control addresses over 60% of the overexposures experienced by coal miners. The adoption of real-time RCS monitoring by operators and mine safety professionals would have a positive impact on miner health by not only providing real-time feedback regarding exposures, but also by enabling informed decisions about changes in controls and behavior, with the goal of reducing exposures to airborne hazards in the workplace. Real-time RCS monitoring would also empower miners to reduce their exposures by altering their work practices that are contributing to their personal exposure. In addition, NIOSH is establishing a repository of characterized elongate mineral particles samples to support toxicology research [NIOSH 2020e] 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 [Bugarski et al. 2020a,b].

Intermediate Goal 1.2: Workplace solutions are adopted that reduce miner overexposure to noise

Activity Goal 1.2.1: (Intervention 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.

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 [Masterson et al. 2013]. 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) [Tak et al. 2009]. 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 [NIOSH 2018]; 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, providing solutions to improve those areas. Some inspectors, specialists, and MSHA Technical Support personnel 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 the primary noise-generating components of machinery and, in turn, by 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 Inc. 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 [NIOSH 2008a] and drill bit isolators to reduce noise exposure during underground coal roof bolt drilling [NIOSH 2012a]. 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) [Smith et al. 2007], a dual sprocket chain on a CMM [Kovalchik et al. 2008], and noise controls for roof bolting machines [Azman et al. 2015].

Future research will expand on the quiet-by-design approach through partnerships with manufacturers to design and install controls on 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 [NIOSH 2020h]. The results of this research 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.

Intermediate Goal 1.3: Workplace solutions are adopted to reduce the effects of environmental factors on miners

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

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 [NIOSH 2019a]. However, heat illness incidents among miners are likely underreported, especially if they do not lead to lost workdays. Heat strain has adverse consequences to health and safety, outside of directly causing heat illness. It is associated with increased injury risk among workers, likely related to a combination of fatigue and reduced cognitive and psychomotor function. 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 an 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 [Hunt et al. 2013]. 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 [MSHA 2003]. 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), 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 [NIOSH 2020k] can assist workers in identifying imminent decreases in mental performance and increases in risk of illness or injury in themselves as well as in 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 [NIOSH 2017a]. 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.

Intermediate Goal 1.4: Workplace solutions are adopted that enable mines to remediate risk factors for musculoskeletal disorders

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.

Burden

Of all nonfatal occupational injuries and illnesses reported to MSHA from 2006 through 2015, just over one-third (34%) were musculoskeletal disorders (MSDs) [Weston et al. 2016]. 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—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 [NIOSH 2004]. Unusual postures and restricted spaces often exacerbate the exposure and risk [NIOSH 2006b]. 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 [NIOSH 2008b]. More recently, ErgoMine, an Android application created by NIOSH, has delivered over 2,200 recommendations to miners in the first year after being published [NIOSH 2016a]. ErgoMine 2.0, 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 [NIOSH 2019b] These impacts will be achieved through significant field studies and interaction with miners, laboratory studies, and continued surveillance of injury and illness data.

Intermediate Goal 1.5: Workplace solutions are adopted that reduce morbidity and mortality of chronic diseases in mining

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

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 subsectors (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. Gaps also exist in understanding the current state of CWP and its prevalence with respect to mine characteristics such as geological conditions, operating conditions, geographical information, and regulatory compliance history. 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 subsectors 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 [Kecklund and Axelsson 2016].

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 complex survey data (e.g., National Health Interview Survey, NHIS), workers compensation, State-based medical centers, MSHA, and industry-based sources. Health data may be collected 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 [NIOSH 2020a]. Building on this resource, the proposed work will help to establish a foundation for a surveillance program called the Miner Health Program [NIOSH 2020b], 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.

Strategic Goal 1: Future Directions

Research on exposure to airborne dust and diesel contaminants is critical for miner health. There is a need to collect data to better understand the fundamental characteristics of mine dust particles including particle size, shape, compositions and their links to health outcomes. Information on commodity-specific and even mine-specific dust particle samples and characteristics can help develop more accurate prediction models. Research also needs to focus on nanoparticles, and ultrafine aerosol particles, such as diesel particles, to understand their toxicology and better understand the health effects of exposure to these particles. It is essential to understand the influence of particle size and number on health outcomes and the toxicity of diesel particles along with possible interactions with respirable crystalline silica. In terms of RCS, robust training datasets are needed along with the development of novel segregation and sample collection methods. There should be a focus on new RCS evaluation methods (such as Partial least squares (PLS) for optimizing the resolution and accuracy of current analyses methods such as FTIR and expanding spectral analysis to the entire spectrum (beyond the quartz doublet), especially for more complex mineral compositions. Although NIOSH has the resources to support this work, collaborating and partnering with experts in the field of toxicology, geology, minerology, chemometrics, and spectroscopy will be essential. Actively working with government agencies to help inform policy and decision making is essential as well.

NIOSH has developed technologies for RCS sampling and monitoring. The next step would be to help use developed technologies, such as the continuous personal dust monitor (CPDM), as part of a more holistic approach to reducing exposures to RCS and commercialization of real-time RCS monitoring systems. There is also an opportunity to conduct cross disciplinary research, such as incorporating human factors considerations like noise measurement, whole body vibration, and physiologic measures into developed technologies like Helmet-CAM. With the surge in unmanned automated vehicles (UAVs) and drones for commercial purposes, these technologies can be leveraged for dust and gas sampling in both underground and surface mines. Finally, as NIOSH continues to work on dust suppression, isolation, and measurement systems, new and novel systems should be continually explored, including canopy curtains and air filtration kits, while simultaneously optimizing current solutions for different commodities and locations, including use of resources like water for dust suppression.

Based on number of nonfatal incidents and burden associated with musculoskeletal disorders (MSDs), there is a continuing need to reduce these health hazards. Musculoskeletal health assessments and work assessment tools are needed for both small and large mines. In addition, research is needed to reduce MSDs related to manual material handling and slips, trips, and falls, and those injuries caused by overexertion that lead to strains and sprains. Emerging technologies, like exoskeletons and process automation, are being used in other industries to reduce the negative health effects on workers. The efficacy of using exoskeletons and other emerging technologies should be evaluated for the mining industry as they relate to MSDs.

From a miner health perspective developing quieter mines and quieter equipment can lead to a reduction in hearing impairment. An emphasis on the quiet-by-design approach would provide proactive solutions for manufacturers. In addition, continuing to explore both singular and multi-source hazards (e.g., ototoxic, vibration, etc.) of hearing impairment is critical to mitigate exposure and risk. With recent advances in and an emphasis on automation, technology and the Future of Work, there is a need to investigate the health effects associated with implementing these systems and other attributes of Healthy Work Design (HWD). Conducting studies on conditions that affect readiness-for-work (e.g., mental health, substance use/misuse, fatigue) as well as completing studies to understand organizational commitment to safety, health, and well-being, and the impact on worker health and quality of life should be considered. Finally, as presented though the Miner Health Program Strategic Agenda, there is a need to move away from a siloed approach to mine worker health and to shift focus towards a more holistic approach to miner health and well-being that concurrently considers all health aspects through monitoring, implementing interventions, evaluation, and community engagement.

Strategic Goal 2: Reduce mine workers' risk of traumatic injuries and fatalities

The mining sector utilizes a wide range of tools, stationary equipment, and mobile equipment to extract and process mined materials, many of which can pose immediate harm or death to miners. The mine itself can also pose significant hazards by way of roof and rib falls in underground mines and ground failures at surface mines. Surface and underground mines and the associated processing plants pose a variety of hazards, some of which change as mining progresses. Unintended interactions between miners and these hazards can result in outcomes ranging from acute traumatic injuries to life-threatening trauma and fatal injuries.

In 2020, there were 23,844 underground coal workers, 39,772 surface coal workers, 13,246 underground M/NM workers, and 220,047 surface M/NM workers exposed to the various hazards in the mining industry. These 296,909 workers worked approximately 496.2 million hours during 2020 [NIOSH 2022]. Also, in 2020, powered haulage and machinery were involved in 15 fatalities and 592 lost-time injuries in underground and surface mines, while falls of ground, electrical, and slip or fall of person were involved in 9 fatalities in underground and surface mines. [NIOSH 2022].

Slips, trips, and falls remain a significant factor in traumatic injuries, and fatigue and other fitness-for-duty issues play a significant role in increasing risk of injury. Although work-related deaths in the mining industry were at an historic low in 2016 [U.S. DOL 2017], the need remains for research devoted to preventing fatalities. Specifically, research to address fatalities caused by machinery and powered-haulage accidents—as well as fatalities caused by slip or fall of a person; falls of ground; and falling, rolling, or sliding rock—remains critical in reducing traumatic injuries in mining.

Below, in support of Strategic Goal 2, each intermediate goal is followed by a series of activity goals—as defined earlier in the Plan—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.

Intermediate Goal 2.1: Workplace solutions are adopted to eliminate fatalities and injuries related to mobile and stationary mining equipment

Activity Goal 2.1.1: (Intervention Research) Conduct studies to develop and assess effectiveness of interventions aimed to improve mine worker hazard recognition and risk assessment capabilities.

Activity Goal 2.1.2: (Intervention Research) Conduct studies to develop and assess the effectiveness of interventions to reduce machine-related injuries and fatalities in mining.

Activity Goal 2.1.3: (Intervention Research) Conduct studies to determine barriers to manufacturers’ implementation of evidence-based design criteria for interventions to reduce machine-related injuries and fatalities in mining.

Activity Goal 2.1.4: (Intervention Research) Form partnerships and alliances to develop products to prevent machine entanglements during maintenance and repair activities.

Activity Goal 2.1.5: (Basic/Etiologic Research) Conduct basic/etiologic research to better understand the human-machine interface, operator decision-making, and injuries among mine workers.

Burden

According to MSHA data analyzed by NIOSH [NIOSH 2020], from 2011 to 2020, a total of 316 fatalities occurred in mining. Metal/nonmetal mining operations (including stone, sand, and gravel) had 177 fatal accidents and coal operations had 139. Of this total (316), 53.8% (170) were related to machinery or powered haulage. Many powered haulage incidents frequently involve larger equipment, such as haul trucks, that have decreased visibility or blind areas due to their extreme size and pose an increased risk for collision-type accidents [CSIRO 2007, Turner 2017]. Other haul-truck related accidents result from the vehicle being backed over a dump point or driven over a berm. These types of incidents involving a haul truck frequently result in fatal or serious injury. Other causes of fatalities included entanglements with conveyor systems, especially for tasks associated with machine maintenance, repair, or cleanup.

Maintenance accidents made up a large portion of machine-related incidents. Maintenance related activities were involved in 15.3% of total fatalities (48) in mines, most frequently due to being caught in/under/between moving or stationary objects, and entanglements, primarily with conveyor belts during maintenance. Maintenance activities also include building/property maintenance, underscoring the fact that maintenance and repair can include any tasks or activities required to repair equipment that stopped working or was not working properly, to replace or recondition components (scheduled maintenance), or to complete upkeep of facilities (e.g., cleaning up spillage). Circadian disruption and fatigue resulting from shiftwork, which is common in coal mines and metal mines, can also contribute to traumatic injuries. Recent data on risks associated with mining shiftwork are sparse; however, an analysis of various industry sectors, including mining, concluded that relative risk for accidents increases across three shifts, with the first shift being the lowest and the third shift being the highest [Folkard and Akerstedt 2004].

Need

The NIOSH Mining Program is uniquely positioned to perform research on machinery, maintenance, and powered haulage safety, with significant experience in designing engineering controls to prevent pinning and striking accidents. NIOSH has completed extensive research in proximity detection systems technology to improve the performance of proximity detection systems being used in underground mines [NIOSH 2020l]. The research findings have been incorporated in MSHA regulations and proximity detection systems for continuous mining machines (CMMs) in underground coal mines [MSHA 2015a]. This research is being extended to proximity detection systems for other mobile equipment as well as for surface applications. For mobile equipment, the main categories of fatalities and injuries suggest that specific machine interventions such as stopping a vehicle before it strikes a pedestrian, detecting berms and edges, and detecting pedestrians around corners and through curtains, are necessary to preclude these types of accidents from occurring in the future. Technologies are currently available and in use that can assist in preventing potentially harmful interactions with mobile equipment such as haul trucks. These range from basic devices such as mirrors and cameras to more advanced collision warning and avoidance systems (CXSs).

An MSHA assessment of fatal accidents at U.S. surface mining operations from 2003 to 2019 concluded that using a CXS could have prevented 23 accidents that resulted in 25 fatalities [Wharry 2019]. OEMs and aftermarket CXSs offer the potential for reducing the risk of accidents at surface mining operations. Although CXSs are currently used at mining operations worldwide [Goodbody 2016; Gleeson 2018; Moore 2018], there is a perception of risk associated with using noncompulsory safety technologies and a degree of uncertainty as to their readiness and fit to be successfully implemented at mine operations in the U.S. [MSHA 2018a; MSHA 2018b; MSHA 2018c; MSHA 2018d; MSHA 2018e]. NIOSH has the facilities to conduct full-scale testing (e.g., electromagnetic interference testing) on mining machines and equipment using specialized equipment such as different proximity detection technologies, spectrum analyzers, and magnetic field probes in a controlled environment. NIOSH research on haul truck health and safety issues identified the need for intervention research, including CXS validation and change management, as part of a larger systems-based strategy for addressing haul truck fatalities and injuries [Bellanca et al. 2020]. Human factors also play a critical role in investigating routine and nonroutine maintenance activities, including risk perception and situational awareness considerations for the use of new technologies [Yorio et al. 2015], and the acceptance and safe maintenance of these technologies.

A strong need exists for improving performance- and system-based standards around workers, technologies, and the organization. Initial research sought to understand what specific leading indicators and respective practices operated under certain risk management elements and how they could best be measured [Haas and Yorio 2016]. Additional work needs to be done to determine how well these systems actually perform and to consider how technology acceptance and integration impacts operationalized risk management practices. NIOSH’s industry partnerships allow for rapid development and implementation of technologies based on Mining Program research, with an understanding of the end user’s perspective on accepting these technologies. NIOSH lighting intervention research can also potentially reduce traumatic injuries. Researchers have conducted extensive human subjects research and have the needed equipment, lighting, and protocols.

Impact

MSHA references NIOSH findings in numerous regulations, giving evidence to the NIOSH Mining Program’s impact on machine safety research for both mobile and static equipment. Specifically, MSHA cited NIOSH research in promulgating the use of proximity detection systems on CMMs and in the final rule for the use of these systems on other mobile equipment [MSHA 2015a]. The industry has adopted emerging technologies and engineering controls based on NIOSH research, which has also guided manufacturers in the design of commercially available systems. As one example, the Hazardous Area Signaling and Ranging Device (HASARD), invented by NIOSH, has been adopted by manufacturers of all MSHA-approved systems installed on CMMs and other types of mobile equipment [Schiffbauer 2001]. MSHA predicts that as many as 70 injuries could be prevented and 15 lives could be saved over the next ten years by utilizing proximity detection systems on mobile haulage equipment in underground coal mines [MSHA 2015b]. Based on MSHA’s economic analyses on regulatory impacts, this equates to approximately $512,000 for each injury prevented and $9.2 million for each life saved, for a total of over $173 million.

Broadly, this research can identify leading indicators that are more realistic in relation to technology development, measurement, and improvement, as well as show the safety advantage of having an operational risk management system through the application of human-technology, organization-level interventions. Analogous types of impact are anticipated from NIOSH research involving mobile surface equipment. Guidelines for addressing issues related to CXS detection performance for surface mining haul truck applications will help reduce disability and death associated with haul truck accidents. Adoption of NIOSH guidance for system validation and change management is expected to improve system efficacy and, in turn, promote industry adoption. Test methods, collaborations, and guidance will help direct future research, support efforts for validating CXS, and advance autonomous haulage. The primary human-centric lighting intervention outcomes include a reduction in circadian disruption and new knowledge about human-centric lighting efficacy in mining applications. In summary, NIOSH research will help the mining industry reduce incidents of injuries and fatalities involving mobile and stationary mining equipment.

Intermediate Goal 2.2: Workplace solutions are adopted to eliminate fatalities and injuries caused by global geologic instabilities at underground and surface mines

Activity Goal 2.2.1: (Basic/Etiologic Research and Intervention Research) Conduct studies to recognize and determine characteristics associated with ground instability to reduce injuries and fatalities in mining.

Activity Goal 2.2.2: (Intervention Research) Conduct studies to develop and validate stress assessment models and mine design guidelines and software to reduce global ground-control-related injuries among mine workers.

Activity Goal 2.2.3: (Intervention Research) Conduct studies to develop and assess global stability recommendations for mine development near gas well casings to reduce injuries and fatalities in mining.

Activity Goal 2.2.4: (Intervention Research) Develop guidelines and best practices and determine barriers to effective implementation of methods for reducing dynamic failures to reduce injuries and fatalities in mining.

Activity Goal 2.2.5: (Intervention Research) Develop mine design and ground control recommendations and determine barriers to effective implementation of methods for challenging underground and surface mining conditions to reduce injuries and fatalities in mining.

Burden

Although the total number of mines, miners, fatalities, and injuries has been on a downward trend in recent years, the near misses, injuries, and fatalities associated with and attributable to ground control failures are distributed among many failure types. Moreover, the number of accidents resulting in worker injury—as opposed to those that qualify as reportable only—have shown a steady increase. These include rib falls, roof falls, massive collapses, bursts, bumps, back failures, dynamic failures, skin failures, highwall failures, slope failures, pillar failures, rock outbursts, insufficient barrier pillars, insufficient standing support, and intrinsic support.

Injuries from ground falls are reported to MSHA, while reported ground fall incidents show the potential for exposure to ground falls that could result in injury or fatality. In relation to ground fall injuries between 2011 and 2020, there were 43,504 surface injuries and 23,209 underground injuries among all sectors, with 39 surface and 2,917 underground injuries related to ground control failure [NIOSH 2020]. Of the 39 surface injuries, all were due to failures of highwall; 9 of the 39 were fatalities and 20 resulted in lost time. Of the 2,917 underground injuries, 36 were fatalities and 1,971 resulted in lost time. Of the 2,730 operator underground injuries, 2,458 (90.0%) were in coal, 232 (8.5%) were in metal and nonmetal, and the remaining 40 (1.5%) were in the stone sector. Of the 187 underground injuries to contractor employees, 148 (79.1%) were in coal and 39 (20.9%) were in other commodities. In relation to ground fall incidents, between 2011 and 2020, there were 45,422 surface incidents and 29,337 underground incidents among all sectors, with 76 surface and 7,110 underground incidents related to ground control failure [NIOSH 2020]. Of the 76 surface incidents, all were failures of highwalls; 9 of the 76 were fatalities and 20 resulted in lost time. Of the 7,110 underground incidents, 36 were fatalities and 1,971 resulted in lost time. Of the total, 6,620 (93.1%) were in coal and 490 (6.9%) were in all other sectors.

This 10-year data provides insight into how ground control failures contribute to accidents and fatalities in mines. As near-surface mineral deposits are depleted, underground mining is occurring in more challenging conditions at depth. Conditions in deep mines stretch the limits of current mining practices, and geologic instabilities become a primary hazard for underground miners among the most difficult problems to mitigate. The depth of mining results in high stress from both in-situ tectonic loads and overburden. The altered stress field can also cause rock mass movement, such as triggering slip along geologic faults. The interaction between underground longwall coal mining and shale gas production received attention only after the Pennsylvania Department of Environmental Protection (PADEP) issued a request to update the 1957 PADEP Gas Well Pillar Guidelines in November 2012. The PADEP and MSHA recognized that the 1957 guidelines were formulated without longwall mining and were inadequate for application to modern-day longwall mining.

More than 1,500 unconventional shale gas wells have been drilled ahead of longwall mining in the Pittsburgh Seam. A few of these shale gas wells, typically drilled through the center of longwall abutment pillars, have recently been mined-by in West Virginia and Pennsylvania, and casing deformations have been documented. These shale gas wells, whether tapped into the Marcellus or Utica Formations, possess high gas volume and high (350~5,500 psi) gas pressure. Longwall excavations could induce high stresses and deformations in the abutment pillar, which could transfer the stresses and deformations to the gas well casings to compromise the mechanical integrity of the production, intermediate, and coal protection casings. Such a compromise of casing integrity could introduce high-pressure, explosive gas into underground mine workings and trigger mine explosions.

Need

To address geological instabilities leading to ground-control-related fatalities and injuries, a mix of basic, intervention, and translation research is needed. Although significant advancements in the understanding of global failure mechanisms that lead to large-scale instability and rock falls have been made, some underlying factors and triggers have yet to be discovered. Further, the physical properties of the strata surrounding the mined opening, which contribute significantly to the stability of the openings and the need for additional support, need to be better understood. Previous projects conducted by NIOSH have investigated these problems, and future projects will continue to improve miner safety through refined models, better risk assessments, and additional knowledge and understanding. The new information combined with the historical research conducted by NIOSH and the United States Bureau of Mines (USBM) provide the best opportunity to eliminate mining injuries and fatalities related to ground control failures.

There is also a need to establish a new ground control safety standard for the deep underground metal mining sector and the shale gas sector. For the deep underground metal mining sector, this effort would involve developing new technologies and methodologies to manage the highly stressed rock mass at depth. Data from seismic networks and geotechnical instrumentation need to be analyzed and interpreted in real time using advanced hazard analysis software to help alert miners to emerging hazards. Furthermore, advanced mechanical excavation and automation technologies need to be developed to reduce many of the current health and safety risks by ultimately removing the underground miner from hazardous working conditions. For the shale gas sector, the longwall-induced unconventional subsidence, where significant horizontal movement occurs along planes of weakness, is not completely understood. This is especially true within the longwall pillar system, where movements may trigger localized or global ground control failure.

Therefore, there is a need to establish ground control safety standards for shale gas wells embedded in longwall abutment pillars. However, besides the 2014 study by the coal and gas industries and the recent NIOSH study, the database is limited. Therefore, it is imperative to enhance the database by collecting and analyzing actual mine-by case data and to investigate all possible factors that may influence longwall-induced stresses, deformations, and permeability changes within the abutment pillar, which may transfer stresses and deformations to gas well casings to trigger gas well casing failure and the release of high-pressure shale gas into underground mine workings.

Several resources unique to NIOSH provide the Mining Program with the most comprehensive research abilities in the world, such as the mine roof simulator (MRS), the high-energy, high-displacement test apparatus, two research/experimental mines to test, calibrate, and experiment with instrumentation, and experts in the various facets of ground control [NIOSH 2020f]. Currently, NIOSH research efforts have developed and continue to bolster cooperative relationships with numerous mining companies (in all commodities), gas operators, federal and state regulatory agencies, all 13 universities with accredited mining engineering programs, several consulting groups, various support and equipment manufacturers, and industry stakeholders.

Impact

As evidenced by previous Mining Program ground control research, impact can range from dissemination of information to small groups of stakeholders to influencing policies and standards. The most immediate anticipated impact is dissemination of information for improved designs, understanding, or follow-on research. NIOSH-developed software programs—e.g., Analysis of Longwall Pillar Stability (ALPS), Analysis of Retreat Mining Pillar Stability (ARMPS), and Analysis of Multiple Seam Stability (AMSS) [NIOSH 2020g]—are outputs of a well-developed research program that led to policy changes, ultimately resulting in a major reduction in injuries, fatalities, and difficult mining conditions. Similarly, numerous standing supports, roof bolts, shield designs, mine designs, shotcrete guidelines, and pillar designs developed through NIOSH research efforts have been adopted by the mining industry. Instructive materials on roof bolting, screen installation, and best practices have been adopted by mining industry trainers, and most recently the software program S-Pillar has been applied to the underground stone sector.

Current projects will continue to increase the awareness of issues with rear abutment, stone pillar design, full extraction load redistribution, ground deterioration monitoring best practices, and entry design through discussions with stakeholders, presentations, and other dissemination techniques. Research in the metal/nonmetal sector will improve the overall safety of deep metal mines by evaluating and developing alternative mining and backfilling methods, squeezing ground assessment strategies, and seismic hazard analyses. These methods will help mines to manage the high-stress fields created by excavating rock at depth and reduce ground falls resulting from both time-dependent deformation and sudden dynamic failures. Research in the shale gas sector will provide engineering guidelines to federal and state regulatory agencies as well as the coal and gas industries to ensure proper pillar design and gas well setback distance to prevent ground control failure within the pillar, which may lead to catastrophic gas well casing failure and dangerous shale gas inflow into underground mine workings to trigger mine explosion.

Intermediate Goal 2.3: Workplace solutions are adopted to eliminate fatalities and injuries caused by rock falls between supports or loss of containment from damaged ribs

Activity Goal 2.3.1: (Intervention Research) Conduct studies to develop and assess the effectiveness of ground control systems and rib support guidelines to prevent ground and rib failures.

Burden

Ground falls remain a leading cause of fatalities in underground coal mines. From 2011 through 2020, a total of 26 ground fall fatalities and 1,792 nonfatal days lost (NFDL) injuries were reported by MSHA [NIOSH 2020]. Of these ground-fall-related incidents, 17 fatalities and 433 NFDL injuries were caused by rib falls. The injuries and fatalities attributable to ground control failures are distributed among causes ranging from pillar failures to rock outbursts to insufficient standing support. Coal rib stability will continue to become a greater challenge as mining operations move into deeper reserves and encounter more adverse multiple seam stress conditions.

Rib-related hazards are most likely to occur in the eastern coal basins of Appalachia and Illinois, which, according to a 2020 Annual Coal Report from the U.S. Energy Information Administration, represent 85.4% of all underground coal mined in the United States [U.S. EIA 2020]. Ground falls in underground metal, nonmetal, and stone mines resulted in 10 fatalities and 173 nonfatal days lost from 2011 through 2020 [NIOSH 2020]. Falls of ground are caused by a breakdown in the ground control system, which is designed to stabilize the rock surrounding an underground opening. Causal factors are often related to seismicity, corrosion, support density or capacity, span opening, and rock mass structure. Several of the fatalities and many of the injuries were related to installing and/or rehabilitating support, especially where this work was accomplished with jackleg drills.

Need

To address fatalities and injuries resulting from ground falls due to the failure of support systems, a mix of basic, intervention, and translation research is needed. This research requires an improved understanding of the mechanisms and the root causes that lead to rock and rib falls, a practical protocol to quantify the structural integrity of coal ribs, an engineering-based coal rib design approach, and a definition of the minimum design requirements for rib control. Previous NIOSH Mining Program research has led to improved recommendations, best practices, and risk reduction methods. Nevertheless, lab testing, field instrumentations and observations, statistical analysis of empirical data, and numerical modeling are needed to expand knowledge and datasets beyond current experience.

Several resources unique to NIOSH provide the Mining Program with the most comprehensive mining research abilities and facilities in the world, including a mine roof simulator; high-energy, high-deformation support system test machine; two research/experimental mines to test, calibrate, and experiment with instrumentation; and recognized experts in the various facets of ground control [NIOSH 2020f]. In addition, strategies and tactics for identifying and managing geologic features that increase the risk of rock mass failures in underground bedded deposits are needed for both coal and nonmetal mine operators. By identifying the critical characteristics of near-seam features associated with dynamic failure events, operators would be able to target preventative support systems and mitigation procedures prior to worker exposure.

Impact

Recent NIOSH research provides a specialized model to simulate the stress-driven coal rib failure mechanisms observed in U.S. underground coal mines. NIOSH is currently using this model to identify critical parameters affecting coal rib stability and to develop an engineering-based design methodology [NIOSH 2020c]. A design procedure will be provided that is similar to the NIOSH software products—e.g., the Coal Mine Roof Rating (CMRR), Analysis of Roof Bolt Systems (ARBS) [NIOSH 2020g], and Support Technology Optimization Program (STOP) [NIOSH 2020p]—which have led to improvements in the analyses of ground conditions and improved control techniques, ultimately resulting in a major reduction in injuries and fatalities and facilitating solutions to address difficult mining conditions. The developed rib design product will enable the mining industry and enforcement agencies, such as MSHA and state agencies, to assess rib integrity and to design appropriate rib controls.

Other research projects are actively exploring the development of design criteria for durable support systems and detecting and managing dynamic failures resulting from anomalous geologic features near coal seams [NIOSH 2020d]. Detailed geologic characterization of near-seam features and monitoring of ground behavior over time using seismic monitoring and novel geophysical and geochemical approaches will aid in the identification of specific mine locations at risk for dynamic failure phenomena. A full understanding of hazard location and ground support systems performance will provide a foundation for developing measures to control or remove ground control hazards.

The impact of this research will be measured directly by the safety performance achieved, and the long-term impact will be measured by the surveillance of ground control injury data for the underground mining industry when the new technologies and best practices are generally adopted. A reduction in the number of injuries and fatalities due to ground falls in underground mines will be expected to result from this research. For the metal/nonmetal sector, impact will be assessed by working with several western underground mines to install new long-term support systems at their mines and qualitatively monitoring their performance over time to determine if there is the predicted reduction in ground falls. Improvement is anticipated in the overall stability of the mine and of the individual stopes and drifts, as well as the long-term survivability of the support system elements.

Intermediate Goal 2.4: Workplace solutions are adopted that enable mines to remediate risk factors for slips, trips, and falls

Activity Goal 2.4.1: (Basic/Etiologic Research) Conduct studies to determine environmental factors associated with slips, trips, and falls.

Activity Goal 2.4.2: (Intervention Research) Conduct studies to develop tools and interventions to allow mine workers to identify and remediate slip, trip, and fall hazards.

Burden

Slips, trips, and falls (STFs) of a person are the second largest contributor to nonfatal injuries in the U.S. mining industry. Slips, trips, and falls accounted for 25.3% of nonfatal injuries and led to 597,544 days lost from work during the period from 2011 to 2020. Slips, trips, and falls also led to fatalities and accounted for the deaths of 26 miners at surface coal and surface metal/nonmetal facilities from 2011 through 2020 [NIOSH 2022]. Publicly available MSHA reports describing fatalities at surface mining facilities [MSHA 2020] reveal that mechanic/maintenance man, off-road haulage, and warehouseman/bagger/palletizer were the job categories associated with a large proportion of fatalities. Maintenance and repair, climbing scaffolds/ladders/platforms, getting on or off equipment/machines, welding/cutting, and walking/running have been shown to be hazardous tasks and were also found to result in STF fatalities. The most common contributing factor was the lack of adequate fall protection or inappropriate use of a personal fall arrest system. Inadequate barriers, equipment-related factors, and a lack of adequate operating procedures were also identified as contributing factors.

Need

Although well established as a major source of injury, STF hazards are still widespread in the mining industry. Several factors contribute to workplace STFs, including environmental factors such as inadequate lighting and poor housekeeping, personal factors such as not maintaining three points of contact when climbing ladders or wearing fall protection, and equipment-related factors such as limited equipment access and damaged or poorly designed ingress/egress systems. There are few mining-specific resources available that can be readily used to prevent STFs at mine sites. Hence, there is a need to investigate and provide recommendations and tools to identify and remediate the environmental, personal, and equipment-related factors that contribute to STF injuries and fatalities in mining. In its well-established Human Performance Laboratory, NIOSH is actively pursuing project research to develop recommendations for footwear based on empirical evidence from lab testing and to identify features of mobile equipment ingress/egress systems that pose an STF risk [NIOSH 2020o].

Impact

Guidance is needed to inform mining companies about how to change the workplace or work practices to prevent STFs. Current Mining Program research will inform the development of a toolkit, with multiple tools, to identify, report, and remediate STF hazards in a timely manner. A study by NIOSH’s Human Performance Laboratory will identify if there are changes in gait, toe clearance, and heel clearance when wearing metatarsal boots as compared to regular safety toe shoes during ascent and descent from stairs and inclined walkways. Results from this study will inform mine policy and practices by providing miners and mine managers with the knowledge to determine when to replace footwear based on wear patterns and decreased tread depths. Reducing risk factors for STFs by modifying the environment, improving personnel practices through effective training and policies, and utilizing safer equipment will directly impact the mining industry. Providing mine sites with tools and recommendations that can be used to identify and remediate STF risk factors will have a significant impact on costs to the industry and improve the health and safety of miners.

Intermediate Goal 2.5: Workplace solutions are adopted to identify, measure, and improve miners’ readiness for work

Activity Goal 2.5.1: (Basic/Etiologic Research and Intervention Research) Conduct studies to develop, assess the effectiveness of, and identify barriers to utilizing fatigue management systems to reduce the effects of fatigue on mine workers.

Activity Goal 2.5.2: (Basic/Etiologic Research and Intervention Research) Conduct studies to determine and reduce the occupational risk factors associated with inexperience in the mining industry.

Burden

Many work and nonwork factors can contribute to an individual’s readiness for work on a daily level. Broadly speaking, these factors can include fatigue from shiftwork, long commutes, sleep disorders, physical fitness or limitations, experience in a job position or task, and stress, mental health, and cognitive impairments. As mining technologies have evolved toward a greater amount of automation, job tasks for individual miners have also evolved, and the spectrum of required work capacity has broadened. Several studies have described the increased workload capacities required during specific mining activities [Harber et al. 1984; Stewart et al. 2008; Saha et al. 2011]. Mining is susceptible to worker fatigue due to a combination of environmental, organizational, and personal factors; however, the exact burden of fatigue in mining is largely unknown. Fatigue can be influenced by dim lighting, high temperatures, loud noise, highly repetitive and monotonous tasks, long work hours, sleep disorders, and circadian disruptions resulting from shiftwork, long work hours, and generally poor sleep habits. Similarly, physically demanding jobs require a certain level of physical fitness to maintain readiness and performance.

As the physical and mental demands of mine work activities continue to be studied, the knowledge, skills, and abilities acquired through prior job and task experience have increasing importance in managing work safety. Inexperience is a known risk factor for workers in many industries, including mining [Butani 1988]. Experience levels for injured workers are tracked by MSHA. In 2017, MSHA and other NIOSH stakeholders expressed concerns about the higher number of injuries and fatalities for miners with less experience [MSHA 2017]. Preliminary analysis of incident data from 2006 to 2017 shows that miners with less experience make up a high number of injured workers in both coal and noncoal sectors. However, workplace promotion of fitness or readiness for work has recently expanded its context beyond consideration of experience with job tasks and the physical, social, and cultural work environment to include focal areas such as improved nutrition, eliminating drug or alcohol use, emphasizing the importance of rest and sleep to combat fatigue, and training. Nevertheless, the application of worker initiatives to monitor or improve miner readiness for work has not been widely institutionalized or promoted in the United States, nor has any strategic guidance been provided.

Need

Whether considering the contributing factors to worker fatigue or physical fitness levels, the current knowledge of mining workforce readiness is limited. Information is often (1) anecdotal and unsupported with reliable measures; (2) focused on a specific sub-population of the workforce (e.g., underground coal, haul truck operation, mine rescue); (3) based on cross-sectional data representing one point in time; or (4) limited with respect to shiftwork details. A multilevel approach based on research and implementation may help address mine worker readiness for work. Best practices, or solutions toward improving and maintaining a worker’s readiness, are needed in the mining industry.

In order to provide informed guidance, components of readiness need to be characterized along with measuring any associations with injury, illness, recovery, and return-to-work time. These efforts should evaluate for differences in job task demands and individual age, along with how these and other nonwork factors change over time and over the course of one’s career. Then, appropriate resources and targeted workplace solutions can be designed and evaluated for effectiveness to help improve and maintain miner performance and quality of life. There is also a need to understand the relative effectiveness of specific interventions for managing mine worker fatigue depending on the type of fatigue, the type of mine, and the individual variation among workers. With respect to shiftwork, lighting interventions are effective for reducing circadian disruptions and fatigue because the day/night cycle of light impacts circadian rhythms. NIOSH also has distinct advantages and unique resources for conducting research involving the testing of human subjects; thus, researchers have extensive experience with mining equipment, mine environments, job demands, human subject protocols, and human factors applied research. NIOSH has a history of collaboration with industry and expertise in industrial hygiene and epidemiology, positioning the Mining Program to lead efforts to obtain and analyze data, consider privacy issues, and clearly communicate program objectives. The recent establishment of the NIOSH Miner Health Program [NIOSH 2020b] will provide the mechanism for conducting this work.

Impact

Since 1957, the National Health Interview Survey (NHIS) has provided data that can be used to track health status, health care access, and progress toward achieving national health objectives in the United States [CDC 2018]. Numerous studies have demonstrated how a healthy workforce will improve production, job satisfaction, reduce the burden of injury and illness for both the employee and employer, and promote longevity and functionality of individuals into retirement. Health promotion programs can help prevent work-related illness or injury, and numerous workplaces have instituted policies, programs, and incentives to enable and promote a healthier workforce. Establishing systems to regularly assess the health and well-being of miners will enable individual companies to design and evaluate worker health programs that target inefficiencies in employee readiness for work, while reinforcing continued maintenance of healthy behaviors and components of well-being.

Mining Program solutions and strategies that have proven to be effective and sustainable will be highlighted and disseminated across mining sectors and other appropriate industries. Given that inexperience is a known risk factor for injury, the impact of efforts to reduce the safety gap related to inexperience will be tangible both to the miner and the mine operators. Improved information and tested training products for operators, supervisors, and/or line workers, delivered to industry via the NIOSH website and conferences, will enable industry to address key areas identified through the research. Through systematically evaluating the effectiveness of multipronged mine worker fatigue initiatives, NIOSH and the mining industry could develop validated tools to attenuate fatigue health and safety issues through concrete translational solutions and scientific validation. If these tools are properly implemented and disseminated, NIOSH could have the opportunity to recommend evidence-based guidance for fatigue management systems in the mining industry. Together, these efforts should lead to a reduction in inexperience-related injury rates.

Strategic Goal 2: Future Directions

Ground control failures have the potential for catastrophic consequences such as the massive collapse of pillars in room-and-pillar and longwall mines, the potential for gas inundation when pillar retreat mines and longwall mines interact unfavorably with sand channels creating methane and stress issues, the potential for surface mine highwall failures due to new highwall mining processes, and the triggering of large seismic events that can cause extensive damage to mine workings. Continued research is needed for ground control interventions for both underground and surface mines. In underground mines, there is a need for tools that can be used in the field to predict when rib support is needed along with information on effective supports for various ground conditions.

Similarly, there is a need for remote intelligent roof-fall indicators that warn of imminent roof falls and can be used from a safe distance. Research should also identify if and what types of entry stability systems are needed when longwall shearers come to the end of the panel and cut into the recovery entry. One approach that could be used involves seismic networks to monitor for coal bumps, rock bursts, and collapse. Current S-Pillar research can be expanded and improved by adding case histories to improve pillar design and entry support systems for other commodities, for multi-level quarries, and for deep mines. As there is an increase in the potential opportunities enhancing safety through reduce exposure through automation, tools and other monitoring should be investigated to assist these processes to ensure coal miners health and safety.

At surface mines, there should be a continued focus on ground stability related to mine highwalls and bench design, with an emphasis on design, monitoring, and alarms for highwall stability. A better understanding of mechanical properties of soft rock mines and highwall miners is still needed to design stable and safe evacuations in weak strata and multiple seam undermining. Advanced methods to design and monitor surface mines slopes should be explored, especially at soft rock mines and geological anomalies. Research on ground stability related to slope and highwall monitoring and alarms, bench design, and improved sensors for seismic monitoring and analysis should be conducted. In addition, advanced technologies such as the use of unmanned aerial vehicles (UAVs and drones) for monitoring should be explored.

In general, the monitoring and mitigation methods for ground support degradation should be investigated at both surface and underground mines. Devices to monitor long-term deterioration of mine openings in mines, especially in stone mines, to avoid potential massive collapses would improve safety. There is a need to better understand the mechanical properties of entry openings and to enhance the current NIOSH analysis of coal pillar stability research relative to geologic conditions and mining stresses. Additionally, a need exists to develop engineering interventions to prevent massive strata collapses in underground stone mines by identifying factors that are responsible for the collapse, developing methods to evaluate risk, and evaluating mitigation strategies. Finally, ground support requirements should be explored for using autonomous equipment at surface and underground mine sites.

Recently advanced technology and automation has received significant attention in mining as a solution to help reduce traumatic injuries. However, there is a need to ensure these systems are designed and implemented so that they do not pose a health hazard or create new safety risks. Two overarching themes that should be considered when implementing new technology is to adopt a systems engineering approach with a focus on human factors engineering, and to work in collaboration with other research organizations. Adopting a systems engineering approach for any intervention ensures that all aspects of the work system are considered, including the miner, tasks performed by the miner, equipment and tools used, the work environment, and organizational and external factors.

Similarly, when investigating safety risk, there should be a more holistic view focusing on human factors and systems safety. It is also essential to ensure that the organization implementing these new technologies has adequate change management practices in place that these work practices are adopted as part of any intervention and implementation process to ensure its success. Finally, other personnel at mines including contractors should be considered from the standpoint of awareness, response, and training. Due to the complexities associated with advanced technology and automation and the number of different stakeholders involved, it is critical to work both collectively and individually with OEMs, technology integrators, universities, and mining companies when developing these technologies.

The NIOSH Mining Program is ideally suited to track trends in automation and access the health and safety effects, organizational changes (work process, job duties, training, maintenance), and other factors related to acceptance and implementation of automation. Similar work should be carried out on sensors (intrinsically safe/permissible and others) and wearable devices that may be part of the technology advancement. With the increased attention on automation and automated vehicle use, additional research is needed on wireless communication (vehicle to vehicle and vehicle to human), human-machine interface design, control/dispatch room design, level of driver assistance, miner situational awareness, trust in automation, driver distractions, collision avoidance, warning systems, illumination, roadway design, traffic control, and maintenance.

Research is also needed as it relates to emergency control, signal-noise detection (faulty, inaccurate sensors), and operator and equipment response to spurious signals. For semi-autonomous and fully autonomous mobile equipment, there should be an additional focus on collision prevention and avoidance, especially for people-machine collisions but also for machine-machine collision. Collaboration between workers and automated systems is expected as the trend towards more fully automated systems evolved. Finally, a human-centered approach should be taken for the design of any planned interventions or technology adoption, ensuring appropriate function allocation rather than implementing technology just because it is available.

Tied closely with advanced technology and automation is data. As more data is collected from and fed into the work system, there needs to be a focus on integration, analysis, interpretation, visualization, and sharing of big data along with using big data to inform interventions and risk assessment. The right data, given in the right way and at the right time, will help to enhance situational awareness and therefore decision making and allow subsequent actions that are appropriate and effective.

Strategic Goal 3: Reduce the risk of mine disasters and improve post-disaster survivability of mine workers

Historically, mine disasters such as fires, explosions, inundations, and roof falls have been the driving force behind both enactment of mining laws and regulations and government investment in mining health and safety research. Fatalities have occurred as a direct result of these events but have also occurred when workers were unable to successfully escape, to isolate themselves from toxic atmospheres to await rescue, or when rescuers perished during a rescue attempt. Although mine disasters have become less frequent, the hardship arising from recent mine disasters is still strongly felt by the families of the 12 miners who barricaded themselves at the Sago mine following the 2006 explosion, with 11 suffocating in the toxic atmosphere, the 6 miners and 3 rescuers who died in the Crandall Canyon pillar collapse in 2007, and the 29 miners who perished in the Upper Big Branch explosion in 2010 [MSHA 2019b].

Lives can be saved through improved technologies and practices to limit the occurrence of mine disasters. These technologies and practices include more effective applications of rock dust and improved control of float coal dust to limit accumulations of the explosible fuel source, more effective bleeder designs to limit accumulations of methane gas in bleeder entries and to maintain the proper split of ventilation airflow at longwall tailgate corners, improved techniques for identifying incipient stages of a mine fire and the spread of toxic contaminants throughout active workings, and improved identification of conditions and mechanisms that lead to instability of rock masses. Improvements in post-disaster escape strategies and technologies such as mine refuge alternatives (RAs), emergency communications, emergency evacuation decision making, and survivability of critical systems such as mine-wide atmospheric monitoring, communication, and tracking systems could increase the chances of worker survival.

NIOSH disaster prevention research can reduce the human toll of mine disasters by removing or limiting the conditions under which a disaster can occur. Improved strategies and technologies for self-escape and for use by mine rescue personnel will provide the industry with much-needed tools to enhance miner survivability in the event of a disaster. Accordingly, this work addresses accumulations of combustible and explosible materials; detection of hazardous conditions; catastrophic failure of mine pillars, stopes, and critical structures; mine worker self-escape; and post-disaster survival and rescue of mine workers.

Below, in support of Strategic Goal 3, each intermediate goal is followed by a series of activity goals—as defined earlier in the Plan—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.

Intermediate Goal 3.1: Workplace solutions are adopted to reduce the risks associated with accumulations of combustible and explosible materials

Activity Goal 3.1.1: (Intervention Research) Conduct studies to develop and assess the effectiveness of float dust controls to reduce the risk of injury associated with coal mine dust explosions.

Activity Goal 3.1.2: (Intervention Research) Conduct studies to develop guidelines for mine development near gas wells and casing design criteria to reduce the likelihood of gas migration into underground mines.

Burden

According to MSHA accident data [NIOSH 2020a], since 2010, 29 U.S. mine workers have been killed and 23 injured as a result of fires or explosions in underground workings. Float coal dust, generated during coal mining, serves as fuel that can propagate an explosion flame, and the explosibility of float coal dust is controlled by applying “rock dust”—i.e., ground limestone dust—on all mine surfaces as an inerting agent. However, based on data from MSHA’s Mine Data Retrieval System [MSHA 2020], the industry received nearly 743 violations in 2020 for failure to maintain rock dust levels sufficient to limit float coal dust explosibility. Accumulations of methane gas are also a constant threat to the safety of underground mine workers. From 2011 through 2020, roughly 49 methane ignitions occurred during coal mining, generally during longwall mining [NIOSH 2020]. Ventilation airflow is the primary means of controlling methane levels, but such controls are challenged by more rapid mine development that liberates greater methane quantities, larger mining areas that create greater exposed coal surfaces, and larger gob areas under the influence of a single ventilation district. Finally, fires in a confined underground mine environment can produce catastrophic consequences. From 2011 through 2020, approximately 808 fires were reported [NIOSH 2020]. When the fire source cannot be readily diagnosed or remedied, the mine may be temporarily sealed by a mine operator until diagnostics indicate that the fire is extinguished. Such an action can greatly stress or ruin the local economies that are dependent upon mine worker wages.

Need

Federal regulations mandate that all underground coal mine surfaces be rock dusted [MSHA 2011]; however, no standard protocol exists for evaluating the inerting performance of rock dust. A previous NIOSH study collected rock dust samples from various mining regions and discovered that nearly half of the samples did not meet minimum particle size requirements; of those that did meet the requirements, some did not inert coal dust [NIOSH 2011a]. This study called into question the effectiveness of rock dust products being used in underground coal mines, demonstrating the need for standard test protocols for use by manufacturers. To reduce disaster risk, effective ventilation on longwall mining units is also critical to controlling the large amounts of methane gas liberated during mining. Specifically, research is needed to quantify potential accumulations of methane at the longwall tailgate corner. Guidance on mine monitoring is also needed so that sensors can be properly deployed to maintain the effectiveness and utility of a monitoring system. Sensor deployment strategies must be developed and evaluated using performance-based metrics to ensure early detection of a combustion incident. The NIOSH Mining Program is uniquely qualified to conduct this disaster prevention work due to the high level of expertise of its researchers and the availability and access to the required laboratory apparatuses and in-mine facilities.

Impact

NIOSH Mining Program successes in reducing the risk of disaster are evidenced by the development of the coal dust explosibility meter [NIOSH 2012b], recommendations for a new rock dusting standard [NIOSH 2010], software products such as MFIRE [NIOSH 2016c], and research on “smart ventilation” [NIOSH 2017b]. Continued research in these areas will develop technologies that limit the generation and transport of float dust at the source and throughout mine workings. In addition, standard test protocols developed by NIOSH will be available to industry suppliers to assess rock dust effectiveness for inerting a propagating coal dust explosion. Mine operators will use NIOSH research findings to improve ventilation to minimize accumulations of methane gas at longwall tailgate corners, and NIOSH will develop new strategies that provide earlier detection of such accumulations along the longwall face area, thus reducing the number of face ignitions [NIOSH 2020m]. Improved NIOSH-developed sensor deployment strategies will be performance-based, permitting early detection of fires and heating in the incipient stages of combustion and, perhaps, forestalling the long-term closure and sealing of the mine.

Intermediate Goal 3.2: Workplace solutions are adopted to improve detection of an reduce the risk of hazardous conditions associated with fires and explosions and ground instabilities

Activity Goal 3.2.1: (Intervention Research) Conduct studies to develop sensor deployment strategies to detect levels of combustible gases to prevent fires and explosions and ground instabilities.

Activity Goal 3.2.2: (Intervention Research) Conduct studies to develop sensor deployment strategies to detect unstable mine opening conditions for prevention of ground control failures.

Activity Goal 3.2.3: (Intervention Research) Conduct studies to develop and assess the effectiveness of interventions to prevent hot surface ignitions on mining equipment.

Activity Goal 3.2.4: (Intervention Research) Conduct studies to develop and assess the effectiveness of interventions to suppress mining equipment fires.

Activity Goal 3.2.5: (Intervention Research) Conduct studies to characterize factors that influence Li-ion battery ignition pressures within sealed enclosures and to develop design recommendations for explosion-proof or flameproof battery enclosures.

Activity Goal 3.2.6: (Intervention Research) Conduct studies to characterize fire in Li-ion battery-powered mining equipment to determine appropriate fire suppression agents/systems.

Activity Goal 3.2.7: (Intervention Research) Develop ventilation recommendations for preventing smoke and toxic gas spread in a mine.

Burden

Mine fires and dynamic rock and coal failures continue to be serious hazards threatening the safety of the mining workforce. From 2011 through 2020, there were 38 bursts reported, with 2.6% of these resulting in fatalities [NIOSH 2020]. Approximately 33% of these events were in longwall mines. There were two additional fatalities in a single event in 2014 during room-and-pillar retreat mining. MSHA mine accident data [NIOSH 2019a] indicate that during 2010-2019 there were 868 reported fires, one fatality caused by mine fires, and 225 injuries caused by flame, fire, and smoke. In metal/nonmetal mines, combustible liquids including diesel fuel, engine oil, and hydraulic fluid come into contact with hot engine exhaust components such as exhaust manifolds and turbochargers. Further, increased use of lithium-ion (Li-ion) battery technologies in mines brings potential failure modes, intensities, and toxicities of large-format Li-ion battery fires that are not well understood [Dubaniewicz and Ducarme 2013]. For permissible battery-powered equipment in gassy mines, there are no MSHA test procedures for assessing containment of Li-ion battery thermal runaway within conventional explosion-proof enclosures designed to contain only methane-air explosions [Dubaniewicz et al. 2020].

Need

Although hot surface ignitions have long been known to cause most mine equipment fires in M/NM mines, the detailed ignition mechanism is still not well understood, leading to the need to identify factors that impact the occurrence of hot surface ignitions. Mine monitoring remains one of the biggest assets to improve detection of and reduce the risk of hazardous conditions, but sensors must be appropriately deployed to ensure the efficacy of the monitoring system and the information it provides. MSHA regulations on sensor deployment are limited and prescriptive in nature. Performance-based deployment strategies are needed for critical underground locations, including battery charging stations and diesel fuel storage areas. In relation to Li-ion batteries, current MSHA battery fire prevention requirements were developed to address lead-acid battery hazards [Battery Assemblies 2018], but do not take into consideration known fire hazards associated with Li-ion batteries. Research is needed to study the failure modes of these batteries, heat release rates of battery fires, gaseous products of combustion, the appropriate fire suppression agents/systems, explosion-proof enclosure design criteria, and overall risk assessment.

The continued occurrence of dynamic events with the potential to cause multiple fatalities underscores the need for further understanding of the conditions and mechanisms that lead to these events. Detailed geological characterization of the surrounding rock mass and the determination of the complete stress redistribution experienced during room-and-pillar retreat and longwall mining are needed to understand and eliminate these rare but catastrophic events. NIOSH is ideally suited to address these issues due to its breadth of knowledge and experiences in developing sensors and sensor arrays to detect hazardous accumulations of combustible gases. Furthermore, NIOSH has the expertise and industry contacts necessary to understand coal bursts and related phenomena and to develop methodologies for predicting and identifying potentially adverse mining conditions.

Impact

Research on mine monitoring will help to address the industry’s major fire safety issues [Yuan et al. 2017]. The development of sensor deployment strategies will help mine operators install those sensors appropriately to detect a mine fire or a hazardous condition in a timely and effective manner [NIOSH 2020m], thus reducing injuries or fatalities from the fire or toxic byproducts. Improved sensor deployment strategies will be performance based, permitting early detection of fires and heatings in the incipient stages of combustion. Lithium-ion battery safety research will advance fire-related knowledge in this area, improving reactions to fires caused by such batteries. Improved geologic characterization will result in better understanding of the intrinsic risk for the release of combustible gases and improved hazard assessment. This work will also establish a solid foundation for developing prevention measures and avoidance forecasting to eliminate burst catastrophes.

Intermediate Goal 3.3: Workplace solutions are adopted to prevent catastrophic failure of mine pillars, stopes, and critical structures

Activity Goal 3.3.1: (Basic/Etiologic Research and Intervention Research) Conduct studies to determine characteristics associated with and development of mine design guidelines to prevent massive or catastrophic failures of mine structures.

Burden

Current NIOSH Mining Program research related to this intermediate goal focuses on underground stone mines. Historically, the large majority of limestone mining has been accomplished through surface mining operations. NIOSH reported that 3,307 crushed stone mines were operating in 2020 [NIOSH 2020]. Of that total, 96 were underground mines. Over the last two decades, the number of surface operations has been decreasing while the number of underground mines is gradually increasing. Since 2011, fatalities related to ground control in underground stone mines have accounted for 4 of the 7 total fatalities [NIOSH 2022]. The reduction in ground fall injury rate in limestone mining has been significantly less than that achieved in coal mining during the past decade. In fact, the ground fall injury rate has increased significantly over the past two years. Likewise, the fatality rate in the underground stone sector has increased overall during the past decade, while the underground coal sector fatality rate has declined. In underground metal mining, deeper mining has led to increased ground stresses associated with mining activity. These increased stress states both contribute to, and are more affected by, seismic energy release, thus increasing the potential and/or severity of seismic events in these mines.

Need

NIOSH developed and made public the first pillar design software program (S-Pillar) for underground stone mining in 2011 [NIOSH 2011b]. This software is designed to meet the pillar design needs of the majority of the underground stone mine industry but does not address several uniquely challenging environments. Stakeholder discussions have indicated that these environments will likely be encountered more often at future mining operations. Further analyses of case histories are necessary to provide detailed assessments of the hazards associated with these insufficiently studied environments. NIOSH is uniquely qualified to undertake this research effort. The organization has had a long history of impactful research in this area, including development of software for analysis of stone pillar stability. Continued efforts will only improve the predictive capabilities of this product. In underground metal mining, NIOSH is positioned well, through the Intermountain Seismic Network (IMSN) in northern Idaho, to address the issue of energy storage in a mining rock mass over time, with particular attention given to the likelihood of sudden energy release from a given portion of the rock mass. Monitoring of this energy buildup, along with the storage potential of the rock mass, is crucial to maintaining a safe mining environment.

Impact

A successful stone pillar stability project will establish a solid foundation for the development of revised or supplemental guidelines for underground stone pillar design [NIOSH 2020q]. Research will likely be performed in underground limestone mines but may be applicable to other hard rock room-and-pillar mines with similar dimensions, depths, mechanical properties, and lithology. For underground metal mine seismicity, the methods of Cumulative Energy and Energy Index will be applied to seismic and structural data for underground areas of interest in order to understand time-dependent trends that could be used in predictive methods. Back analyses based on stepwise mining progression will be conducted to evaluate the change in rock mass response over time. A successful outcome to this work would include the development of best practices for identifying volumes of interest around stopes, methods of hazard level assignments for display and warning to mine workers and operators, and models to evaluate and compare the feasibility of different mining plans.

Intermediate Goal 3.4: Workplace solutions are adopted to improve miner self-escape, rescue, and post-disaster survival

Activity Goal 3.4.1: (Intervention Research and Implementation/Translation Research) Conduct studies to develop and determine barriers to effective implementation of a standardized mine emergency self-escape system.

Activity Goal 3.4.2: (Implementation/Translation Research) Conduct studies to determine barriers to effectively incorporating self-escape competency profiles into assessment activities.

Activity Goal 3.4.3: (Implementation/Translation Research) Conduct studies to assess the feasibility and acceptance of immersive technologies for mine rescue training.

Burden

Mine emergencies have resulted in fatalities even when self-rescue responses and rescue activities were attempted, which raises a number of serious concerns about the preparedness of the U.S. mining industry to respond to mine emergencies. There is evidence that inadequate training of the workforce to effectively identify and respond to the related risks is among the root causes associated with these tragedies [U.S. DOL 2002, 2007, 2011; Mine Safety Technology and Training Commission 2006; U.S. GAO 2007]. Less than optimal technologies are also at fault. For example, MSHA evaluated accident and fatality data from 1900 through 2006 and estimated that 221 lives could have been saved over the 107-year period if refuge alternatives (RAs) had been available [MSHA 2008]. To continue improvement of refuge alternatives, the MSHA final rule provides guidance for the design and implementation of these structures, including structural integrity of RAs, breathable air supplies, air monitoring, the removal of harmful gases, effective communications, and provisions for lighting, sanitation, food, water, and first aid [Refuge Alternatives 2008]. While a significant amount of work has been conducted in the development and integration of technologies to fulfill these requirements, validation of the designs and commercially available products must be investigated.

Need

While it is difficult to quantify or predict the economic and human costs associated with mine disasters, the resulting fatalities serve as a reminder of the critical need to balance investments in resources to reduce the likelihood of high-probability but low-severity events with investments focusing on response to infrequent but high-severity events. NIOSH is an industry leader in the development and testing of emergency response systems [NIOSH 2020n]. As such, the Mining Program can provide the mining industry with critical guidance on future modifications and evaluations of improved systems. Fatalities can be reduced through improved solutions for mine worker self-escape and for survivability of those who fail to escape from an underground mine fire, explosion, or fall of ground. Because of its past research in the areas of self-escape, mine rescue, and post-disaster survivability, the Mining Program is well-positioned to make critical advances in these areas to support mine workers who could be endangered in future events [NRC 2013]. Success depends on monitoring systems, which accurately provide information of contaminated underground atmospheres after a mine disaster; technologies that provide a safe location for refuge with an atmosphere where trapped miners can wait for rescue; miners who evaluate their situations correctly and take appropriate self-protective actions; and mine rescuers who make decisions so they can safely assist miners during emergency events.

Impact

Building on past successful research and development efforts will improve the survivability and applicability of underground post-disaster monitoring systems. For example, rather than drilling boreholes to enable monitoring of the underground atmosphere, which can take days to complete, research will develop more robust environmental sensors strategically located in underground workings that can collect real-time mine data to monitor and lower the risk of hazardous conditions. Such advances will allow the continued flow of critical atmospheric information to mine rescue teams and to underground mine workers. Additional study by NIOSH in miner competence in the knowledge, skills, abilities, and other attributes (KSAOs) required for self-escape post-disaster will develop new self-escape training protocols. Through the application of evidence-based NIOSH recommendations and incorporation of self-escape performance-based training and assessment criteria, mine safety and health training professionals will have the tools necessary to bring all miners to mastery in the physical tasks required for self-escape. Further investigation of refuge alternatives will enable the mining industry to perform accurate evaluations of RAs and to submit approval applications required by MSHA [NIOSH 2020a]. Research on the validation of the designs and commercially available RA products will provide life-sustaining solutions to miners who fail to escape and must take refuge to await rescue.

Strategic Goal 3: Future Directions

Mine disasters can result from a variety of sources and events. These events, such as fires, explosions, inundations, and major collapses of roof or rib can be monitored and even predicted in some cases. Their prevention is of utmost importance, however, any measure provided to improve the survivability after a disaster is critical as well. Regarding explosions, it is essential to find and mitigate potential flammability hazards like organic materials and those associated with refuge chambers which run in an oxygen-enriched environment. Mitigation strategies, based on available knowledge from fires and explosion research, are needed to deploy active and passive barriers that will increase miner survivability by reducing explosion severity and the corresponding complexities of self-escape.

Also, there is a need to develop methods to mitigate existing plugging and endpoint distribution problems associated with long-distance pneumatic transport of rock dust to neutralize coal deposits in longwall tailgate and conveyor belt entries. As battery-powered electric vehicles are involved in more applications in the mining industry, it is important to reduce the hazard of fire and/or explosion of the battery. The hazard is further exacerbated in gassy underground mines where ignition of methane-air mixtures may cause a mine disaster. Research is needed to characterize pressure relief and flame quenching properties of flame arrestors that can be used with lithium-ion battery enclosures to mitigate lithium-ion battery ignited explosion hazards in gassy mines.

Efforts to improve post-disaster survivability must be situated within a context of an overall mine system. Components that would influence self-escape including, but not limited to, training, technology, equipment, and emergency response plans should be explored. In addition, these components should also be considered for other elements like mine rescue, fire brigades, responsible persons, and command centers. Research resources and logistics often require pieces of the emergency response system be identified for individual study, but these pieces should be clearly situated within the larger context of response. For example, new training strategies and technologies should not stop at a single skill but should provide realistic exposure to emergency situations and opportunities for practicing related skills within the context of an overall response. This type of training includes virtual reality or other methods for simulation. These methods have been shown to have success in the recent past and are being built upon for specific training tasks.

A recent expert panel review of the Mining Program highlighted the need for human factors, behavioral science, and social-science-based research, while also considering improvements in technology. This emphasizes that how miners and responders use these technologies is as important as the technology itself. For example, improving the availability and effective use of information could improve emergency decision making. This work could include methods to gather data, such as sensors, with a focus on what data is needed and how it can be optimally presented to escaping miners or responders. Interface design, display technologies, types of data, and the timing of the delivery of data are all topics that could increase the effectiveness of sensor or other equipment solutions and increase the impact of NIOSH past and future work in this area. Additionally, the panel suggested that there is a need for social and behavioral research to understand mine workers’ responses to emergencies, including stress, and how miners may react in emergencies. Information from similar industries, such as firefighting and the military, can be used to inform research on mine workers response to emergencies.

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NIOSH [2011a]. NIOSH hazard ID 16—non-conforming rock dust. U. S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2012–102, HID 16, 2011 October:1–4.

NIOSH [2011b]. S-pillar—software for stone mine pillar design. Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, 2011 Jan.

NIOSH [2012a]. Bit isolator reduces drilling noise in underground coal mines. Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2012-110, TN 548, 2012 March; :1–2.

NIOSH [2012b]. Technology for real-time monitoring of coal dust explosion hazards. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2016a]. ErgoMine application. Pittsburgh, PA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH), 2016 Apr.

NIOSH [2016b]. EVADE software. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2014–134c, 2016 Dec.

NIOSH [2016c]. MFIRE software. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2017a]. Heat stress: a series of fact sheets for promoting safe work in hot mining settings. Spokane, WA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication Nos. 2017-123; 2017-124; 2017-125; 2017-126; 2017-127; 2017-128.

NIOSH [2017b]. Smart ventilation to control airborne pollutants and physical stressors in underground metal/nonmetal mines. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2018]. Noise controls for jumbo drills used in metal/nonmetal mines. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2019a]. MSHA data file downloads. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2019b]. Slip, trip, and fall prevention for mining. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020]. MSHA data file downloads. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020a]. Advancement of refuge alternatives for underground coal mines. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020b]. Clinical and field data analysis of miner health. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020c]. Design methodology for rib control in coal mines. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020d]. Detecting and managing dynamic failure of near-seam features in coal and nonmetal mines. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020e]. Developing a roadmap and reference materials for minerals and materials research. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020f]. Facilities. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020g]. Ground control software toolbar. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020h]. Increasing the effectiveness of targeted mining hearing conservation program elements. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020i] NIOSH mine and mine worker charts. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020j]. NIOSH strategic plan FYs 2019–2023. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020k]. Noise mining program partnerships. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020l]. Predicting the impact of heat strain on cognitive functions in miners. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020m]. Proximity detection. Topic webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020n]. Real-time method to characterize a mine fire using atmospheric monitoring systems and MFIRE 3.0. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020o]. Rescue Technologies and Training. Topic webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020p]. Slip, trip, and fall hazard identification, investigation, and remediation at surface mining facilities. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020q]. STOP - Support technology optimization program. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

NIOSH [2020r]. Underground stone mine pillar design in challenging conditions. Project research webpage. U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health.

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Appendix A

Past Projects That Informed This Strategic Plan

Appendix B

Table representing five major mining subsectors served by the Mining Program; metals, industrial minerals, crushed stone, coal, and sand and gravel. The table represents these subsectors as classified by MSHA and Standard Industrial Classification (SIC).

NEC = not elsewhere classified