What lies beneath

Traveling down its main street, Stawell seems like any other regional center in Victoria, Australia. There’s a town hall with a clock tower, a couple of menswear shops, a pub, a post office – most housed in grand old buildings that date back to the 19th century.

But Stawell has something else. Continue up the hill, turn right and wind your way across a tussocked ridge, and an imposing processing plant comes into view. It’s the most prominent landmark on Stawell Gold Mine’s surprisingly compact site. Otherwise, there’s a series of neatly arranged office buildings and workshops and, at the bottom of the site, a gravel ramp that descends, steeper than you might think, to a gaping hole in the rock face.

Stawell has been the location of gold mining of one sort of another since 1853. Back then, it was alluvial operations in Pleasant Creek. Now, it’s this intimidating, arch-shaped portal, which runs north back towards the town, but this time deep underground into more than 300 kilometers of tunnels that reach more than one kilometer below the surface.

“This is part of the Golden Triangle,” says Stawell Gold Mines general manager Troy Cole. “Stawell, Ballarat [to the east] and Bendigo [to the north] have been responsible for in order of 70 to 80 million ounces of declared gold production. The region is historically one of the richest gold provinces in the world.”

And gold is making a comeback on the back of demand from central banks and its perception as a safe haven for investments, but also because of its use in a technology industry supercharged by the rapid adoption of AI.

BUT WHERE mining for gold was once as simple as walking down to the creek with a pan and a shovel, now it’s about drilling down deep under the surface of the earth. To do that cost effectively, you need best-in-class equipment, and Stawell Gold Mines is eager to show us one piece in particular.

We load into Mobile Plant Maintenance Superintendent Jake McInerney’s neatly kept LV, circling past the mill before descending towards the portal. Passing through into the mine, the vivid country sunlight quickly gives way to an enveloping darkness, the LV’s headlights kicking in as we turn left and the decline steepens further.

McInerney takes us down, down and further down past fenced off adits, whirring ventilation fans and banks of blinking control boxes neatly fixed to the mine’s shotcreted walls.

After six or seven minutes we round a corner and what looks like a piercing pair of red eyes slowly begins to emerge from the gloom.

“There it is,” McInerney says and slows the LV to a crawl. As we approach, the vision quickly fills out into the imposing backside of a jumbo drill rig.

Operator Glenn Walker maneuvres the 14-meter-long rig through an elbow in the tunnel and down another incline to a towering rock face. The levelling feet extend to stabilize the rig before its two enormous booms unfold, spider-like, to begin the thunderous work of boring, bolting and meshing.

This is one of Stawell Gold Mines new Epiroc Boomer M20 S jumbo rigs. The performance results of this rig reported by Epiroc’s Fleet+ telematics software, as well as Stawell’s own systems, are nothing short of staggering – with the M20 at one stage achieving an impressive 8 390 development drill-hole-meters in one week and offering on average a 15 percent improvement in drill-meters-per-hour over the mine’s existing jumbos – but watching one in person is something else.

Cole will tell you the earth that surrounds what’s known as the Magdala gold deposit is competent rock, but it’s no match for the sheer force of the Boomer M20 S. The jumbo’s rockdrills punch into the ceiling meters above the mine face, great chunks of tumbling basalt not enough to turn it from its task.

In the rig’s air-conditioned cabin, Walker efficiently moves between two touch screens, one for each boom, using the onboard Rig Control System RCS 5 to set them into a choreographed subterranean dance. It’s a stark contrast to the levered physicality of previous machines.

“Those gains are due to less time scaling, less time marking up,” McInerney says. “They get that nice profile because they have the RCS 5 rig control system onboard, which gives them something to reference from.”

The other thing that strikes you when watching Walker in the cabin is how much visibility he has.

The Boomer M20 S boasts the world’s first hoseless design, with all the hydraulics contained within the booms themselves. It’s a game changer for operators who, without great looms of hydraulic cabling attached to the front of the machine, have clear lines of sight across the mine face, helping with safety, efficiency and uptime.

“Often if you see downtime on a jumbo, it’s a hose that’s damaged,” says mining superintendent Jeremy Sargent. “As much as we try to wrap them, there’s still wear and tear, so you spend a lot of time changing them out when they’re blown or doing preventive maintenance.

“Also, on a purely hydraulic system, those hoses and valves need to run into the cab. If you blow a hose, you have the potential for it to happen inside the cab, which can be an absolute headache to rectify.”

Walker says not having the hoses running into the cab on the Boomer M20 S also has an effect on comfort, with the rig’s air conditioning not having to overcome the extra heat they generate.

“Operators can be skeptical of new equipment,” Walker says. “But once you get used to it, you realize, ‘It’s not going to take my job’. It’s the opposite. It makes things more consistent and predictable, taking away that anxiety. The rig simply makes your job more enjoyable, meaning you can keep doing what you do for longer.”

STAWELL TOOK delivery of its first Boomer M20 S two years ago (a second arrived on site at the start of the year) but McInerney and Sargent reckon its already impressive gains are only just the start, as Epiroc works with the mine team to roll out its ABC Total automation software, which enables drilling of an entire sequence of holes automatically using a digital drill plan.

“Over the past six weeks we’re up to 600 holes drilled using what we call supervised automation, so that’s letting the machine do its boom movements and finding its drill position automatically,” McInerney says.

“That’s a small percentage of total holes drilled, but in the scheme of things, every month if the average rig is drilling 24 000 meters a month, we’re getting maybe 2 000 meters on top of that.

“We ultimately want to run it over shift changes and get more of those free meters.”

“This all has to do with that full support we get from Epiroc,” Sargent adds. “Over those weeks they’ve always been here, training the operators and making sure the rigs do what we expect.”

“It’s been a great journey with Epiroc over more than 20 years,” Cole says. “They’ve provided commercial and corporate support for what we’re trying to achieve here, and we reciprocate that through participation and enabling their products to be developed within our site.

“Embracing technological change helps you stay innovative and also stimulates the workplace. It makes you realize the importance of those long-term partnerships. They’re a huge part of what we do here.”