The Unexpected Silence of Battery-Electric Drilling at MMG Rosebery

The first thing you notice is what's missing.

Standing in the dimly lit tunnel 900 meters below Tasmania's surface at MMG Rosebery mine, veteran drill operator James Harmon braces for the familiar assault on his senses. The air should be thick with diesel particulates, the temperature several degrees higher from engine heat, the rock walls vibrating with mechanical fury. Instead, there's just the soft whir of electric motors and the rhythmic percussion of drill steel against rock as the massive Epiroc Simba E70 S battery-electric production drill bores into the tunnel face.

"It's almost unsettling at first," Harmon admits, running his hand along the drill's control panel. "Twenty years underground and your body expects certain things – the heat, the noise. But after a week with this rig, going back to diesel feels like stepping backward in time."

The 34-tonne, 14-meter-long rig with its 150 kW battery system represents Tasmania's first battery-electric drill, bringing dramatic environmental improvements to the underground workspace. The reduction from the typical 116.2 decibels of pneumatic drills to around 102 decibels means conversations no longer require shouting. Vibration levels have dropped to roughly one-fifth of what pneumatic equipment produces. Most importantly, the elimination of diesel particulates has transformed air quality in working areas where miners spend eight-hour shifts in confined spaces.

Three months into the implementation, shift supervisor Megan Collins watches from the control station as Harmon interacts with the drill's touchscreen interface. "The biggest challenge wasn't the technology," she explains. "It was rewiring how our people think about their jobs."

Where operators once physically controlled every aspect of drilling, the Simba E70 S has shifted their role dramatically. As Mikael Larslin, Global Product Manager at Epiroc puts it: "As the process becomes more automated, the operator goes from running the drill to supporting it."

This transition required completely rethinking operator training. Rather than focusing on equipment handling, Collins developed a program emphasizing data interpretation and process optimization. The drill's advanced control systems enable performance tracking that allows continuous evaluation through production reporting.

"The resistance was real," Collins admits. "These are people who've built identities around hands-on skills. Now we're asking them to become process managers who support the automation rather than drive it directly."

Collins recalls one particularly skeptical veteran who initially refused to engage with the performance tracking system. "He'd been drilling for 15 years and didn't need a computer to tell him how to do his job," she says. "Then we showed him how the data identified a pattern of bit wear he'd never noticed. Now he's one of our strongest advocates for the technology."

The transformation extends beyond operator roles to MMG Rosebery's bottom line. Despite the higher initial capital investment for battery-electric equipment, the operational economics tell a compelling story.

Electric mining equipment operates at costs 56% to 88% lower than diesel-powered alternatives, a reality already demonstrated at Rosebery through previous implementation of low-emission diesel-electric loaders that reduced fuel consumption by 170,000 liters. In a similar trial with hybrid loaders, the mine achieved a 56% reduction in fuel consumption and a 15% reduction in heat generation during a two-month period.

These efficiency gains contribute directly to financial performance. MMG reported a 58% increase in EBITDA to US$123.2 million, attributed partly to operational improvements including the implementation of battery-electric equipment.

For General Manager Steve Scott, the environmental metrics are equally important. "We're seeing measurable improvements in underground working conditions," he explains. "The elimination of diesel particulates means better air quality for our people. The reduced heat generation makes the working environment more comfortable. And the decreased noise and vibration levels reduce fatigue and improve communication."

These benefits align with MMG's broader sustainability goals, including a 30% reduction in Scope 1 and 2 greenhouse gas emissions by 2030 from a 2020 baseline, and ultimately achieving net zero carbon emissions by 2050.

MMG Rosebery's journey with the Simba E70 S offers a blueprint for mines considering similar technology. Scott emphasizes that success requires looking beyond equipment specifications.

"The technology itself performed as expected," Scott explains. "The implementation challenges were about integration – rethinking maintenance schedules, establishing charging infrastructure, and most importantly, preparing our people for different roles."

The mine's approach to charging infrastructure proved particularly critical. Rather than treating it as an afterthought, MMG integrated charging station planning into their overall mine design, ensuring optimal placement for operational efficiency.

For Harmon, who initially questioned whether he could adapt to the new technology, the transformation has been surprisingly rewarding. "I used to measure success by how much rock I moved," he reflects, studying the performance metrics on his screen. "Now I'm thinking about optimization, efficiency, and yes, environmental impact. I'm not just operating a machine anymore – I'm managing a process."

As he initiates the next drilling sequence with a few taps on the touchscreen, the Simba E70 S responds with quiet precision. In the newfound silence of the tunnel, you can almost hear the sound of an industry transforming.