The mining industry confronts critical challenges in ensuring worker safety, particularly in underground operations. Recent data from the International Council on Mining and Metals (ICMM) reveals a troubling pattern: 42 fatalities across 24 member companies in 2024, up from 36 in 2023 and 33 in 2022. Underground mining accounts for 43% of fatal incidents, underscoring the urgent need for comprehensive safety strategies that protect workers while maintaining operational excellence.

The Economic Case for Safety

Emerging research challenges the traditional view of safety as a cost center. The 2025 EY Global EHS Maturity Study demonstrates a direct link between safety investments and business performance. In Canada, 70% of industry executives confirmed that health and safety initiatives directly improve financial results, while 85% attributed operational efficiency gains to robust Environmental, Health, and Safety (EHS) approaches. Investors now recognize that a strong safety track record mitigates risks and enhances long-term organizational value, making comprehensive safety strategy a competitive differentiator in the mining sector.

Leadership and Cultural Transformation

Addressing safety challenges requires more than technological solutions—it demands a cultural shift. Leadership must establish a safety-first mindset throughout the organization by engaging employees, fostering open communication about potential risks, and promoting proactive risk management. This transformation involves transparent reporting of safety concerns, comprehensive training programs, clear accountability mechanisms, and a collective commitment to worker protection.

Technological Innovations in Safety Management

Advanced technologies enable the transition from reactive to proactive risk management. Integrated EHS platforms and real-time data analytics identify potential control failures before they escalate, provide early warning systems, and enable precise risk assessment and mitigation strategies.

The Path to “Zero Harm”

The concept of zero harm represents a comprehensive approach to operational excellence. By integrating safety into core business strategies, mining companies can protect workers while driving organizational performance. Key strategies include continuous risk assessment, investment in advanced safety technologies, comprehensive training programs, cultural transformation, and leadership commitment to worker protection.

Conclusion

Underground mining safety requires a holistic approach that recognizes safety as a strategic imperative rather than a compliance requirement. By doing so, the mining industry can create environments that protect workers, enhance operational efficiency, and drive sustainable growth. The sector’s long-term sustainability depends on an unwavering commitment to safety.

North American Regulators Move to Curb Diesel Exhaust in Underground Mines

Regulators in the United States and Canada are tightening rules on diesel particulate matter in underground mines, launching fresh measures beginning in 2023 and a newly issued proposal in July 2025 to reduce workers’ exposure and address a long-standing occupational health gap that contributes to respiratory disease and premature death among miners.

Announced two years apart but targeting the same hazard, the initiatives by Ontario’s Ministry of Labour, Immigration, Training and Skills Development and the U.S. Mine Safety and Health Administration (MSHA) represent a coordinated North American effort to reduce diesel exhaust below levels previously tolerated in metal and non-metal mines. Both governments cite mounting evidence of diesel particulate matter (DPM) toxicity and the need to modernize standards that scientists, unions, and some companies argue are outdated given current technology and knowledge.

While the regulatory details differ, the policy signals align: mining operations relying on diesel-powered equipment in confined underground spaces will face stricter limits, more comprehensive monitoring requirements, and higher expectations to protect workers. Industry groups now have a narrow window to shape final rules and potentially accelerate adoption of cleaner engines, alternative power sources, and enhanced ventilation systems.

Regulatory details on the table

MSHA’s July 1, 2025 notice of proposed rulemaking would revise existing exposure limits from 2001, lowering the permissible concentration of diesel particulate from 160 micrograms per cubic meter of respirable elemental carbon to a level the agency says “better reflects current scientific understanding of health risks.” The proposal, published in the Federal Register, establishes new compliance timetables, monitoring methodologies, and record-keeping requirements designed to improve miners’ safety in underground metal and non-metal operations Federal Register.

Ontario moved earlier. On April 11, 2023, the province adopted amendments to Regulation 854 under its Occupational Health and Safety Act, cutting the time-weighted average exposure limit for total carbon—a proxy for diesel particulate—from 400 µg/m³ to 160 µg/m³, a 60 percent reduction. The rule mandates regular sampling and empowers inspectors to issue stop-work orders when readings exceed the limit. The government described the change as a “significant reduction to protect workers’ health” NORCAT release.

Why diesel exhaust is in the crosshairs

Diesel engines power haul trucks, loaders, and drilling rigs in underground mining, yet their exhaust contains fine particles that penetrate deep into the lungs. Epidemiological studies link long-term exposure to elevated rates of lung cancer, chronic obstructive pulmonary disease, and cardiovascular problems. In enclosed underground workings with finite ventilation capacity, concentrations can spike quickly, especially in areas with heavy equipment traffic or during ventilation maintenance.

Lower regulatory thresholds require mine operators to upgrade fleets to newer, cleaner engines or transition to electric and battery-powered machinery, expand ventilation systems, and strengthen real-time monitoring. While retrofits and infrastructure investments carry costs, regulators and occupational hygienists argue that health benefits—fewer sick days, reduced compensation claims, and lower mortality—outweigh expenses.

Industry fatality trends underscore urgency

Diesel particulate is one element of a broader safety puzzle, but persistent fatality numbers keep the issue in focus. The International Council on Mining and Metals (ICMM) reports 42 fatalities across 24 member companies in 2024, up from 36 in 2023 and 33 in 2022, with 43 percent of deadly incidents occurring in subterranean environments. These figures amplify the call for comprehensive risk management approaches that encompass air quality as well as geotechnical stability, ground control, and human factors.

Economic incentives align with health goals

The 2025 EY Global EHS Maturity Study reinforces the business rationale for stringent controls: 70 percent of Canadian mining executives surveyed said health and safety initiatives directly boost financial performance, while 85 percent reported operational efficiency gains from robust environmental, health, and safety strategies. Cleaner air underground is increasingly viewed as a competitive differentiator that appeals to investors concerned about social governance metrics and long-term value creation.

Implementation hurdles and opportunities

For U.S. operators, MSHA’s proposed rule triggers a public comment period, after which the agency will publish a final regulation with an implementation timeline spanning several years. The phased approach allows mines time to procure lower-emission engines certified by the U.S. Environmental Protection Agency, install high-capacity particulate filters, or transition to battery-electric fleets. Mines that have already adopted Tier 4 diesel engines or battery and tethered electric vehicles may advance more quickly.

In Ontario, enforcement is underway. Provincial inspectors armed with real-time aerosol monitors can order immediate remediation when samples exceed the 160 µg/m³ threshold. To comply, several operators have increased vehicle maintenance schedules and are testing hydrogen-powered loaders in pilot headings. Others are revisiting ventilation modeling to ensure airflow adjustments keep contaminants below the new ceiling without compromising temperature control or energy efficiency.

Worker participation and cultural change

Regulations provide only one layer of defense. Health and safety professionals stress that frontline workers and supervisors need systematic training to recognize poor air quality indicators and to report exhaust leaks or ventilation failures promptly. Leadership commitment is equally critical. Companies that embed zero harm principles into their management systems—holding supervisors accountable for air quality metrics, embedding safety in performance evaluations, and rewarding near-miss reporting—are more likely to achieve sustained exposure reductions.

Technological sweep boosts detection

Digital solutions accelerate the shift from reactive to proactive controls. Handheld aerosol photometers, fixed sensors linked to Wi-Fi networks, and integrated dashboards provide real-time alerts when particulate levels approach regulatory caps. Such systems enable ventilation on demand, targeting airflow to areas of highest need, reducing both exposure and energy costs. Data analytics also support predictive maintenance, flagging diesel units whose emissions trend upward before they exceed compliance thresholds.

Broader implications for the mining sector

Together, the Ontario rule and MSHA proposal signal regional convergence toward stricter diesel standards. The alignment simplifies compliance for multinational operators and nudges supply chains toward cleaner technologies. Equipment manufacturers have responded by accelerating development of battery-electric underground trucks capable of delivering comparable torque to diesel counterparts, though with higher upfront costs and new charging-infrastructure requirements.

For regulators, the coordinated actions demonstrate responsiveness to scientific evidence while acknowledging technological feasibility. Should MSHA finalize its rule close to Ontario’s current limit, North America would establish a de facto benchmark that could influence jurisdictions such as Australia, South Africa, and Latin America, where underground diesel regulations remain uneven.

Analysis: balancing ambition and practicality

While regulators aim high, the transition poses practical challenges, particularly for smaller mines with limited capital budgets and older fleets. Without targeted subsidies or tax incentives, some operations may defer upgrades, risking non-compliance or reduced output. Governments could mitigate such barriers by expanding grants for electric equipment pilots, streamlining certification for retrofit filters, and facilitating knowledge-sharing across industry clusters.

Equally important is rigorous, transparent enforcement. Standards alone do not guarantee improvement; consistent monitoring, unannounced inspections, and credible penalties are essential. If executed effectively, the new rules could help reverse worrisome health trends and contribute to broader sustainability goals, enhancing the sector’s social license to operate.

Looking ahead

The clock is now ticking. Ontario mines are already operating under tougher rules, and U.S. operators must prepare for finalization of MSHA’s proposal. Collaborative efforts—bringing together regulators, miners, equipment makers, unions, and researchers—will determine whether cleaner, safer underground workplaces become reality. With fatalities still elevated and investor scrutiny intensifying, reducing diesel particulate exposure is no longer optional; it is central to the future of responsible mining.

Sources

• https://www.federalregister.gov/documents/2025/07/01/2025-11619/improving-and-eliminating-regulations-limit-on-exposure-to-diesel-particulate-matter-in-underground
• https://www.norcat.org/government-of-ontario-clears-the-air-with-new-exposure-guidelines