Cummins said it has deployed the world’s first commercial hybrid-electric ultra-class mining haul truck as part of a pilot project at the Caserones copper-molybdenum mine in Tierra Amarilla, Chile, which is 70 per cent owned by Canadian miner Lundin Mining.

The pilot, launched in February, involved using a retrofitted 300 short ton (272.2 tonne) Komatsu 930E haul truck, now powered by Cummins First Mode hybrid technology. Cummins First Mode is a hybrid retrofit kit that combines a Cummins QSK60 diesel engine with a high-power battery system and regenerative braking to reduce emissions compared to standard diesel trucks. Regenerative braking allows trucks to capture energy normally lost as heat during braking, such as during loaded downhill hauls, and convert it into electricity to be stored. 

Early operational results from the pilot have been promising, said Molly Puga, general manager of Cummins First Mode, in an interview with CIM Magazine. Through the first 500 hours of operation, the hybrid unit demonstrated expected fuel savings for the trial version of the technology of approximately 20 per cent. It also lowered the energy passing through the retard grid—an electric braking component that helps slow the truck without overusing the wheel brakes—by 30 to 60 per cent, reducing the risk of grid fires, boosting uptime and lowering maintenance costs. 

Regarding the regenerative braking system, Puga explained that it “thrives in these conditions,” noting that steep downhill hauls are where hybrids excel, capturing significant regenerative energy. Unlike fully battery-electric trucks, Cummins’s hybrid system is optimized to capture high-energy bursts during hard braking, cornering and steep descents. Thanks to its high-power architecture, the braking system supports discharge and recharge rates well above typical set-ups and has been performing beyond expectations at Caserones. 

Cummins is also monitoring how route characteristics influence energy recovery for the truck. Winding routes, for example, generate more regenerative energy than straight paths, said Puga. These insights will help to validate the performance models and could potentially lead to full-fleet conversions and pilot expansions across the Americas. 

System features and operational performance

In the Cummins First Mode hybrid system, six independent batteries, along with power electronics, thermal management system and controls, have been consolidated into a single, integrated assembly that connects directly into the truck’s existing drive systems. Complementing the battery system is the intelligent control software, which optimizes power between the diesel engine and electric battery in real time. By capturing energy through regenerative braking that is normally lost as heat and keeping the engine in a more efficient operating range, the software plays a central role in improving the hybrid-electric truck’s performance and efficiency. 

The battery system is a semi-permanent installation that requires minimal preventive maintenance and is not intended for frequent swapping. Depending on the duty cycle, the batteries are expected to last six to 10 years before a first replacement may be considered, with the unit able to continue operating until the cells are no longer economically viable. 

Currently, the First Mode system is offered as a retrofit kit for on-site installation on existing trucks, but Cummins plans to make it available as a dealer option for new builds in future versions. Puga noted that the system pairs particularly well with trucks undergoing life-extension programs, such as glider rebuilds or engine overhauls, though it can also be installed independently of major maintenance events. 

Engineering hurdles

Several modifications to the Komatsu 930E truck were required to accommodate the First Mode hybrid system, including replacing the truck’s right-hand wing with a reinforced version and strengthening connection points on the truck’s right-hand deck. Puga noted that these changes do not affect the base truck’s function, and the original deck can be restored if the hybrid unit is ever removed. 

Puga explained that the primary challenge in retrofitting an ultra-class truck was adding weight and extra power while guaranteeing seamless integration with its existing engine and drive system. 

“Ensuring the new system interfaced correctly with the drive system and maintaining all existing functionality and safety barriers was a key hurdle, and one we successfully achieved,” she said. 

The second main challenge was structural considerations. Cummins had to remain within the rollover protective structures (ROPS) limits—safety frameworks designed to protect the operator in the event of a rollover—manage stress and potential chassis cracking, while also staying within strict tire performance parameters. Puga noted that the hybrid retrofit had been engineered to meet all these requirements. Komatsu also validated the structural impacts of the truck modifications and confirmed they were within acceptable limits. 

Beyond structural challenges, the high altitudes at the Caserones mine introduced a whole new set of demands on the mining truck. Thinner air and extreme temperature swings can affect engine performance, engine and battery cooling and battery efficiency. According to Puga, Cummins’s thermal-management system had been specifically engineered to ensure reliable operation under harsh conditions. 

Battery temperature—an important factor in system lifespan—remains a focus of research and development at Cummins, where optimized control algorithms and instrumentation en­sure reliable performance at the Caserones mine. 

“[The thermal-management system] provides a significant performance margin and highly efficient cooling, both at the module level and within each battery string,” Puga said. 

So far, the system has kept battery temperatures within nominal limits at Caserones, where nighttime temperatures hover around five degrees Celsius and daytime temperatures reach near 30 degrees Celsius. Puga noted that the high altitude posed no issues, with the truck operating successfully above 4,500 metres. 

Plans for widespread deployment

According to Puga, by the end of the six-month pilot, the Caserones mine could be positioned to move towards a full-fleet conversion, starting with five to six trucks. The pilot has so far demonstrated that hybrid technology can be integrated into existing fleets, providing a practical, scalable pathway to decarbonization by allowing miners to upgrade trucks without waiting for entirely new equipment, she added. 

When it comes to commercialization for the global mining industry, Cummins’s current roadmap begins with launching five to seven retrofitted Komatsu trucks in the Americas. “We are launching pilots at other customer sites, with one planned in Chile in the next quarter, and around the Americas to develop a broader set of mines and customers who have gone through the change management journey, and local service providers who have the skills and experience to scale,” Puga said. 

The company expects to begin full fleet conversions at early adopter mines as operational data from the different pilots accumulate. 

Cummins began developing Version 2 of the hybrid kit in 2025, with plans to increase output to over one megawatt, and continuous charge and discharge rates exceeding one megawatt. Puga noted that the next generation will be built for altitudes of 5,000 metres and above, including other high-altitude locations in Peru and Canada. At those elevations, the primary engineering will focus on ensuring proper electrical creepage and clearance. Version 2 will also offer additional productivity benefits, as well as greater durability and a longer service life. 

Cummins plans to release Version 2 for manufacturing in the first quarter of 2027, allowing the company to begin scaling up to commercial production. 

While diesel engines will remain central to ultra-class trucks, Puga noted that different truck classes and mine conditions will favour different technologies. Trolley and battery-electric solutions can be viable where factors like abundant, low-cost renewable energy and suitable haul routes exist, she added. 

“I believe diesel will continue to have a long future in mining, but wherever diesel remains, hybridization will follow,” said Puga. “A hybrid unit becomes the natural evolution: lowering fuel consumption, enabling decarbonization and improving performance without depending on massive new energy infrastructure.” 

On the importance of partnering with mining companies like Lundin to scale hybrid and electric solutions, Puga emphasized, “It’s absolutely critical. It really does take two to tango, and in this case, it takes a party to line dance. You need local suppliers and service partners—Komatsu and Cummins distributors in this case—to be fully on board.”