The electrification of underground mining fleets is accelerating. What started as limited trials with small equipment has expanded to include production-scale loaders and haul trucks. The implications extend far beyond emissions reduction.

The Diesel Problem Underground

Diesel equipment has powered underground mining for decades, but it comes with significant costs:

Ventilation requirements: Diesel engines produce heat, CO2, NOx, and particulates. Diluting these emissions to safe levels requires massive air volumes. Ventilation can account for 40-50% of underground mine energy costs.

Heat load: Diesel engines are approximately 35% efficient. The remaining energy becomes heat that must be removed from underground workings. At depth, cooling is already challenging.

Health impacts: Despite improvements in engine and filter technology, diesel particulate exposure remains a health concern. Regulatory limits continue to tighten.

Fuel logistics: Diesel must be transported underground, stored safely, and distributed to equipment. This creates operational overhead and safety risks.

Battery-electric vehicles (BEVs) address all of these issues.

The Electric Alternative

Modern mining BEVs match or exceed diesel performance while eliminating combustion emissions:

Zero point-source emissions: Electric motors produce no exhaust. Ventilation requirements drop dramatically – some operations report 30-50% reductions in fresh air requirements.

Reduced heat load: Electric drivetrains are approximately 90% efficient, producing far less waste heat than diesel engines.

Improved working conditions: Underground environments become cooler, cleaner, and quieter. Worker comfort and health improve.

Simplified logistics: Charging infrastructure replaces fuel distribution. While this requires investment, ongoing logistics are simpler.

Current Technology Status

Battery-electric mining equipment has matured significantly:

Load-haul-dump (LHD) loaders: Multiple manufacturers offer production-ready electric LHDs in sizes up to 18 tonnes. These machines have been operating in production environments for several years.

Underground haul trucks: Battery-electric trucks are now available in production sizes. The latest models offer payload capacities comparable to diesel equivalents.

Drill rigs: Battery-electric drill rigs are in development and early deployment. These eliminate a significant source of underground emissions.

Utility vehicles: Personnel carriers, explosives loaders, and other utility equipment are increasingly available in electric configurations.

Charging Infrastructure

The shift from refuelling to recharging requires new infrastructure approaches:

Fast charging stations: High-power chargers located strategically throughout underground workings minimise charging time. Modern systems can add significant range in minutes.

Battery swapping: Some operations use swappable batteries that can be exchanged in minutes. Discharged batteries charge while the equipment operates.

Opportunity charging: Equipment charges during natural pauses – while operators take breaks, during blasting windows, or while waiting for materials.

Trolley assist: On main hauls, overhead power can provide energy while charging batteries. Equipment draws power while moving, extending range.

The optimal charging strategy depends on operating patterns, mine geometry, and equipment fleet composition.

Economic Considerations

Battery-electric equipment carries higher capital costs than diesel equivalents. Batteries are expensive, and the technology is less mature. However, operating economics often favour electric.

Energy costs: Electricity is typically cheaper than diesel per unit of work done, especially when ventilation savings are included.

Maintenance: Electric drivetrains have fewer moving parts and require less maintenance. No oil changes, fewer filters, simpler systems.

Ventilation infrastructure: Reduced ventilation requirements can decrease development costs for ventilation raises and fans. For new mines, this can offset vehicle capital premiums.

Productivity: Faster acceleration and consistent power delivery can improve cycle times. Some operations report productivity gains from electric equipment.

Total cost of ownership calculations increasingly favour electric for new underground operations. Retrofit economics are more challenging, requiring case-by-case analysis.

Transition Challenges

Adopting electric equipment isn’t straightforward:

Infrastructure investment: Charging systems, electrical distribution, and potentially substation upgrades require significant capital.

Mixed fleet operation: During transition, operations must support both diesel and electric equipment. This duplicates some infrastructure and complexity.

Skills development: Maintenance personnel need training on high-voltage systems and battery management. New safety protocols are required.

Range limitations: Battery capacity limits continuous operating time. Operations must be designed around charging requirements.

Battery lifecycle: Battery degradation over time affects performance and eventual replacement costs. Lifecycle management is important.

Industry Leaders

Several operations are leading underground electrification:

Newmont’s Borden mine in Ontario operates as an all-electric underground mine, demonstrating feasibility at production scale.

Evolution Mining’s Mungari operation in Western Australia has deployed electric loaders, reducing ventilation requirements and improving underground conditions.

Glencore, BHP, and Rio Tinto have all announced electrification initiatives across their underground portfolios.

Original equipment manufacturers including Epiroc, Sandvik, and Caterpillar have expanded electric product ranges and invested in technology development.

Environmental Credentials

Underground electrification contributes to mining’s decarbonisation:

Scope 1 reductions: Eliminating diesel combustion underground directly reduces site emissions. For operations powered by renewable electricity, this reduction can be substantial.

Scope 2 implications: The emissions impact depends on electricity source. Operations with access to renewable power achieve greater benefits.

Air quality improvement: Beyond carbon, eliminating diesel emissions improves air quality for workers and surrounding communities.

Mining companies increasingly face pressure from investors, regulators, and communities to demonstrate environmental performance. Electrification provides a tangible response.

Looking Ahead

Underground electrification will continue to accelerate:

Battery technology improvement: Energy density continues to increase while costs decrease. This improves equipment range and economics.

Expanded equipment range: More equipment types will become available in electric configurations, enabling fully electric operations.

Integration with renewable energy: Mines with on-site solar or wind generation can power electric equipment with low-emission electricity.

Automation synergies: Electric equipment is often easier to automate, with precise control and consistent performance characteristics.

The transition from diesel to electric underground is underway. Early adopters are demonstrating benefits that will drive broader adoption across the industry.