Diesel haul trucks represent the largest single source of emissions at most surface mining operations. The industry has been talking about electrification for years. Now we’re seeing real deployments at scale—and learning what works and what doesn’t.

The Current State of Play

Three main approaches are being deployed:

Battery Electric Trucks

Fully battery-powered trucks that charge at pit stops or on the run.

Current deployments:

• Caterpillar’s 793 Electric at testing sites
• Hitachi’s EH4000AC-3 Battery with initial customer trials
• Komatsu’s Power Agnostic truck platform in development

Reality check: These are mostly demonstration units or limited trials. Full production fleets of large battery haul trucks don’t exist yet.

The main challenge is energy density. A 240-tonne payload requires enormous batteries—and those batteries add weight, reducing payload capacity.

Trolley Assist Systems

Trucks run on overhead electric lines for part of their haul, using diesel for the rest.

Current deployments:

• Fortescue Metals Group at Chichester Hub
• Several South American copper operations
• Pilot programs at multiple Australian iron ore sites

Reality check: Trolley assist is proven technology. It reduces fuel consumption by 50-70% on equipped haul roads. The limitation is infrastructure cost and route flexibility.

Hydrogen Fuel Cells

Hydrogen-powered trucks generating electricity through fuel cells.

Current deployments:

• Anglo American’s hydrogen truck prototype in South Africa
• Fortescue’s hydrogen trials

Reality check: Still early. Hydrogen production, storage, and refuelling infrastructure adds complexity. The economics depend heavily on green hydrogen availability and cost.

What We’re Learning from Deployments

Fortescue’s Trolley Experience

Fortescue’s trolley assist system at Chichester Hub has provided the most substantive operational data in Australia.

Results after 18 months:

• 30% reduction in diesel consumption across equipped haul roads
• Initial reliability challenges with catenary systems resolved
• Operators adapted quickly to trolley driving requirements
• Truck productivity maintained (early concerns about speed limitations didn’t materialise)

The main lesson: trolley works best for fixed, long-haul routes with significant elevation change. The ramp out of pits is ideal—trucks use the most fuel climbing under load.

Battery Charging Challenges

Battery trials have revealed charging as the key constraint:

• Charge times of 30-60 minutes disrupt fleet productivity
• High-power charging infrastructure requires significant electrical supply
• Battery degradation in dusty, hot mining environments needs more study

One approach gaining traction: dynamic charging with short charge periods at loading points rather than extended charging at dedicated stations.

Cold Reality of Hydrogen

Hydrogen-powered mining equipment faces challenges beyond the trucks themselves:

• Producing green hydrogen on-site requires significant renewable generation
• Hydrogen storage and handling requires new skills and safety protocols
• Refuelling infrastructure doesn’t exist and must be built from scratch

“Hydrogen is a 10-year journey, not a 3-year solution,” observed one major miner’s technology lead at a recent AusIMM conference.

The Hybrid Transition

Most operations aren’t waiting for fully electric fleets. They’re implementing hybrid approaches:

Reduced diesel consumption:

• Trolley on main hauls
• Battery-electric for lighter support vehicles
• Route optimisation to reduce total haulage

Decarbonisation of remaining diesel:

• Renewable diesel and biodiesel blends
• Improved engine efficiency
• Idle time reduction through automation

This pragmatic approach delivers emissions reductions now while technology matures.

Cost Considerations

Electrification economics vary significantly by site:

Favourable conditions:

• High diesel costs (remote sites with transport challenges)
• Long haul distances with consistent routes
• Available renewable electricity supply
• Operations with 15+ year remaining mine life

Challenging conditions:

• Complex pit geometry requiring route flexibility
• Short-life operations where infrastructure can’t be amortised
• Sites without grid connection or renewable potential
• Extreme temperatures affecting battery performance

A trolley assist system at a Pilbara iron ore operation might pay back in 4-5 years. The same system at a smaller operation with shorter routes might never pay back.

What Operators Should Be Doing

Near-term (1-2 years)

• Audit current diesel consumption by route and elevation
• Identify trolley candidates: routes with high diesel burn, consistent traffic, long remaining life
• Evaluate support fleet electrification for light vehicles and personnel carriers
• Build electrical supply capacity for future needs

Medium-term (3-5 years)

• Plan trolley infrastructure for suitable routes
• Trial battery-electric equipment in controlled applications
• Develop workforce capability for electrical systems maintenance
• Engage with OEMs on equipment replacement timing

Long-term (5+ years)

• Integrate battery and trolley systems as equipment becomes available
• Plan hydrogen infrastructure if site conditions suit
• Target zero-emission haul fleets as economics and technology align

The Vendor Landscape

Equipment manufacturers are investing heavily:

Caterpillar is committed to battery-electric large trucks, with production units expected by 2027.

Komatsu emphasises its “Power Agnostic” approach—trucks designed to accept diesel, battery, trolley, or hydrogen power trains, allowing operators to transition without replacing entire trucks.

Hitachi is focusing on trolley and battery hybrids, with retrofit options for existing fleet.

Liebherr is developing battery-electric trucks for European markets, with larger units to follow.

The common theme: no single technology wins. Successful decarbonisation will mix approaches based on site-specific conditions.

Bottom Line

Haul truck electrification is real but incomplete. Trolley assist works today for the right applications. Battery electric is emerging. Hydrogen is promising but distant.

Mining operations should plan for transition, build infrastructure capacity, and stay engaged with technology development—while maintaining realistic expectations about timelines.

The path to zero-emission hauling exists. It’s just not as simple as swapping diesel trucks for electric ones.