This article is a sponsored feature from Mining.com.au partner Great Boulder Resources Limited. It is not financial advice. Talk to a registered financial expert before making investment decisions.
“The more we drill the more gold we find.”
That is how Andrew Paterson, Managing Director of gold explorer Great Boulder Resources (ASX:GBR), describes the outcome of the company’s exploration efforts so far.
It is an enviable position for any junior explorer to be in, particularly in the gold space, where recently the precious metal has been “breaking records every other day”.
Great Boulder has already established a 668,000-ounce open pittable resource at its Side Well Project in Western Australia and – although its immediate focus is on growing the near-surface resources – is now starting to dig into the depth potential at the project.
Having recently switched back into the discovery phase, Great Boulder is increasingly confident it will grow the project into a large new gold camp.
The resource occupies just 1.1km of strike and remains open to the north for over 1.3km, including the Mulga North Prospect.
In early October, the company began drill testing the Side Well South Prospect, which hosts the two largest and highest-grade auger anomalies identified so far at Side Well – a 2.4km-long Ironbark-style and a 1.4km-long Mulga Bill-style anomaly.
Meanwhile, recent reverse circulation drilling at Mulga Bill has confirmed subvertical gold mineralisation extending up the western side of the deposit, outside of the current resource.
The Mulga Bill Prospect — a 6km corridor of gold and pathfinder anomalism — hosts the majority of the existing resource and has previously returned very high grades of vein-hosted gold up to 3,160 grams per tonne (g/t).
Paterson said previously the results from the latest RC drilling program, which included 4m @ 6.46g/t from 88m, meant Great Boulder would be able to add ounces to the resource at relatively shallow depths with simple tabular lode-style geometry.
He added that “Mulga Bill continues to surprise on the upside”.
“From the work we’ve done so far I think there’s easily potential for a million ounces at Mulga Bill,” Paterson tells this news service.
“Currently we’ve defined a resource of 568,000 gold ounces within the southern half of the overall deposit, down to a maximum depth of around 300m below surface.
“The northern half is a similar scale, mainly defined by shallow drilling. We haven’t completed a resource estimate for Mulga Bill North but we’ll be drilling more holes there shortly.”
The recent RC drilling program at Mulga Bill also intersected mineralisation at depth below the resource.
One hole hit 19m @ 1.25g/t gold from 232m, including 5m @ 2.28g/t from 240m and 4m @ 2.75g/t from 247m.
This is the same zone of mineralisation previously identified 200m deeper in a diamond hole that returned 5.93m @ 3.51g/t from 518.07m, including 1m @ 19.30g/t from 519m.
The extension of these Malvern lodes occurs in what is known as the ‘link zone’ between Mulga Bill’s Central and High-Grade Vein areas.
“We drilled those holes to help demonstrate the scale of Mulga Bill,” Paterson explains.
“We have high-grade assays in drilling spanning more than 2.5km of strike, and these two holes show the system continues beyond 500m depth, as we expected.
“This in itself is an exciting development as it helps illustrate the size of the deposit.
We will follow these up with more deep drilling next year, but for now the priority is to continue finding more open-pittable ounces close to surface.”
Mulga Bill has the same spatial extent as Westgold Resources’ (ASX:WGX) 2-million-ounce Bluebird deposit.
The latest drill results also show much higher grades than expected within the subvertical lodes, which carries “a lot of gold in these areas”.
Great Boulder is planning to investigate this further by undertaking some niche sampling.
This sampling is aimed at arming the company with a better understanding of how the gold grades in narrow pyrite veins compare with the grade of the wall rock around them, which in turn will help Great Boulder understand the mineralisation.
“I suspect the veins are carrying a lot of the metal within a lower-grade halo,” Paterson notes. “It’s somewhat technical, but it helps us understand the grade distribution better.”
Gold camp potential
Great Boulder is targeting 1.5 million ounces in resources at Side Well as it works towards its goal of unlocking a large-scale hydrothermal gold camp in a vastly underexplored area.
The Side Well Project is surrounded by other gold mines and sits less than 25km from Westgold’s 1.8-million-tonne-per-annum Bluebird processing plant.
Over the course of 2024, the company has completed around 35,000m of drilling, confirmed a discovery at Saltbush, added significant grade and length to Mulga Bill and confirmed good continuous zones of mineralisation at Mulga Bill North.
The Saltbush discovery is a +300km-long Ironbark lookalike.
“We’re now drilling the first-pass program over priority targets at Side Well South,” Paterson explains.
“Over the remainder of 2024 we will complete that program, plus more resource definition holes at Saltbush and Mulga Bill North. I think all this work will set us up for rapid gains in 2025.
“Any new discoveries at Side Well South plus the new resource ounces at Mulga Bill North should put us in a good position to reach the 1 million ounce milestone, which will be a fantastic result.”
Expanding its footprint in the Meekatharra region further, Great Boulder in September picked up the tenements along strike from Mulga Bill on the Ironbark Trend.
The +18km Ironbark Corridor is the stratigraphic equivalent of Westgold’s Paddy’s Flat group of mines.
The Ironbark discovery made by Great Boulder currently hosts 100,000 ounces @3.3g/t near surface.
The motivation for the acquisition of the additional ground followed the completion of auger sampling over the Side Well South Prospect which highlighted the scale and intensity of geochemical anomalism heading towards the southern boundary.
“That next block of tenements became an obvious target, and I wanted to grab it in case anyone else had the same idea,” Paterson says.
The owner just so happened to be Great Boulder’s joint venture partner at Side Well South, Mark Selga – an experienced prospector that the company has a good working relationship with.
The agreement adds almost 4km of strike over very prospective geology, which Great Boulder plans to start investigating via regional mapping and auger sampling to generate targets.
These targets will then be tested through aircore drilling, followed by RC drilling. Paterson says the team will probably also extend the gravity survey south to incorporate the newly acquired ground and Side Well South.
Getting ahead of the curve
Paterson believes Great Boulder is one of the busiest, focused junior gold explorers with a clear strategy of organic growth to support a mine development at Side Well.
“We set out a six-month exploration program in July this year and we’ve been ticking each box off the list, month by month,” he says.
“The more we drill the more gold we find, but that’s actually only one side of our story: in the background we also have a number of projects underway to advance Side Well towards development.”
“Mining agreements, mining lease applications, environmental surveys – there are several projects we can work on to get ahead of the curve, pre-development,” Paterson says.
“I don’t tend to talk about these projects a lot, but in fact some of them have been underway for over a year now and they’re all aimed at delivering information relevant to the mining and approvals process.”
Gold may have come off the boil a bit since news of Donald Trump’s US presidential election win broke, but the price of the safehaven metal is up over 24% since the start of 2024 at its current price of around US$2,574 ($3,982) an ounce.
The precious metal holds its value well, having surged over 640% since 2003.
“It’s a fantastic time to be an advanced, high-grade gold explorer with a project in the middle of first-class infrastructure,” Paterson says.
“The gold price is breaking records every other day at the moment. Investors are already looking for opportunities in the gold sector, and the well-positioned juniors will offer the greatest returns.”
Write to Angela East at Mining.com.au
Images: Great Boulder Resources
