Hamelin Gold might just have a ‘winning edge’

When Mining.com.au spoke to Hamelin Gold (ASX:HMG) in December last year, the Perth-based explorer was nearing the end of a ‘biblical’ year. Despite fires and floods in the north-east of Western Australia where its West Tanami Project is located, the company was able to complete 17,500m of drilling and take home three key lessons. 

The first lesson is that shallow drilling just doesn’t work. The Tanami region is encumbered by such extensive sand cover and deep weathering, one must go deep or go home. Second, bismuth makes for a much more effective pathfinder element than arsenic — a fact previously extolled in a report by researchers from the British Geological Survey and the Camborne School of Mines in 2022.

The third lesson — and arguably most important, at least as far as Hamelin’s efforts are concerned — is if ultra-fine soil sampling has proven itself a wildly effective method of exploration at the West Tanami Project, it could be just as effective in the many corners of Australia with similarly challenging, sand-covered terrain.

“In a year or two’s time, if we’re known as the best undercover mineral explorers in the state, then that’s a title I’m pretty keen to hang from the mantlepiece, because I think that’s where the great opportunities are,” Managing Director Peter Bewick says.

We want to be very good at doing that undercover exploration, and that might be what differentiates us and takes us to the next level

“Under shallow cover, there should be just as much metal — if not more — than what we’ve found already in the country. And if we can get better at that, if we can get confidence in some of these new technologies, I think you’ll see another burst of discoveries from it.

We want to be at the cutting edge of that, to be best-in-class in that area. We want to be very good at doing that undercover exploration, and that might be what differentiates us and takes us to the next level.”

‘Tying everything together’

Developed by the CSIRO, in collaboration with LabWest and a number of sponsoring companies, ultra-fine soil sampling has come to hold a pivotal role in resource exploration. 

Specifically designed for investigating areas of deeper cover, the method is based on separating and analysing only the ultra-fine particles — up to 2 microns, or 0.002 millimetres, in diameter — to which metals in transported cover tend to be adsorbed. By eliminating the dilutive effects of much larger sand particles, the enhanced sensitivity can deliver up to a 250% increase in concentrations of metals, particularly gold, copper, and zinc, thereby reducing both the sample size required and the labour involved in collecting it.

Notably, a 2019 study published by researchers from the CSIRO and the Geological Society of Western Australia revealed a marked decrease in censored results for gold, from 63% to 10% below the detection limit.

At Hamelin’s West Tanami Project — prospective for both large-scale gold deposits and nickel-copper-PGE mineralised intrusions — much of this ultra-fine sampling work has focused on the Sultan corridor, where gold mineralisation was discovered in an EIS co-funded diamond drill hole in 2022.

In its report for the December quarter, Hamelin said the ultra-fine soil sampling “provides the most consistent and effective tool to detect gold anomalism within the sand-covered terrains in which we are operating.”

“Such sand-covered areas within the West Tanami have been generally avoided by previous explorers as they were considered too difficult to explore and so represent a significant new exploration search space for the company.”

It’s this connection between the geochemical anomalies and the drilling results which Bewick says is “tying everything together.” And while a major next step will be to bring in some bigger rigs to further test mineralisation at depth, a key factor will be the expansion of ultra-fine sampling across the whole Sultan corridor and the West Tanami Project itself.

“We’ve really only focused on a 1km section that was identified from the geochemistry, and that’s where we’re going to be doing most of our drilling. But at the same time we’re extending the geochemistry along the entire corridor and looking at other similar corridors within our 3,000km-square project where we can apply that geochemistry as well,” Bewick explains.

“We’ve got this relatively new exploration tool which has actually confirmed a connection from surface anomalism to bedrock-hosted mineralisation in shallow drilling, and if we can confirm high-grade mineralisation in deep drilling underneath that, even better. But we think we already know enough to apply this tool elsewhere at the project and we’re really aggressively going to be doing a lot of soil sampling across the project in the next few months.”

Drilling-wise, Hamelin has planned a 1,300m RC program at the Sultan West prospect between March and April this year, targeting gold mineralisation at depth and along strike from that defined in previous aircore drilling. A 1,200m, EIS co-funded program will take place simultaneously at the Sultan Main prospect.

At the Fremlins prospect to the east, a 3km-long surface gold anomaly will be tested — following the completion of a heritage survey and the receipt of regulatory approvals — with aircore drilling early in this year’s field season, while an RC program will target primary gold structure in the second quarter of 2024.

The Olsen and Newkirk prospects towards the centre of the West Tanami Project, however, will be included in Hamelin’s greatly expanded soil sampling campaign before additional drilling takes place.

“In 6 months’ time, we want to definitely understand more about the significance of the gold discovered to date along the Sultan corridor. We’re going to work that very hard over the next few months, not only in the areas we know about, but in the extensions of that corridor,” Bewick says.

“We want to apply what we’ve learned over the last year on the use of ultra-fine geochemistry to screen a number of opportunities across the project, and have them drill-ready hopefully within more like 3 to 4 months than 6. We want to have a very aggressive end-of-year drill program that tests a number of ideas across the project, because we want to really get focused on which prospects within our larger project have the potential to be that multi-million-ounce gold system that we’re looking for.”

The winning edge

If the ultra-fine soil sampling indeed has applications beyond the Sultan corridor, elsewhere at the West Tanami Project, Bewick is willing to take it even further.

“We’re now looking elsewhere in the state and even in the country where this sort of technology can be applied,” he says.

This, Bewick is keen to point out, is the edge that could set Hamelin apart.

“Soil sampling is awfully cheap. If you can rapidly assess an area, bring it down to a real focused area, and just drill through those areas, then that’s the differentiator I think our strategy is trying to pursue: be the best we can in exploring in this sort of environment, and chase those environments where people have given up, maybe prematurely. That might be the sort of winning edge we’re looking for, I suppose,” he says.

It actually showed a gold anomaly twice the amplitude of the shallow drilling that the previous explorers had done

“We can’t talk too much about it, but there’s an area we’ve gone to — an old area that’s undercover and had been drilled by previous explorers — and we ran a line of ultra-fine across that area. It actually showed a gold anomaly twice the amplitude of the shallow drilling that the previous explorers had done.

Where they’d gone along and drilled 3m deep holes, we did surface sampling and got twice what they did in the drilling. It shows that not only is this applicable in the Tanami, it could be applicable in other large areas of the state where surface conditions have meant traditional geochemistry has been ineffective.”

Though it’s part of a need Bewick’s recognised to keep a few projects in the pipeline, rather than relying on just one, unlocking the West Tanami Project remains the most pressing priority. Incidentally, it’s a program of work that’s caught the attention of the world’s largest mining company, too.

Xplor: BHP’s accelerator program

At the end of January this year, Hamelin announced to the ASX its selection for BHP’s (ASX:BHP) Xplor initiative — a 6-month program designed to provide participants with the opportunity to accelerate their growth plans and establish potential long-term partnerships with the mining giant and its global network of partners.

Selected from a pool of more than 500 applicants globally, Hamelin and 5 other early-stage explorers — both public and private — will receive a non-dilutive funding package worth US$500,000, plus access to BHP’s in-house expertise and service providers.

“Over the span of the 6-month program, the 6 companies will work collaboratively with BHP Xplor to expedite the maturation of their geological concepts to position the projects for commercialisation or partnership,” BHP said in January.

“BHP Xplor provides BHP the opportunity to access some of the most exciting exploration prospects globally, enhancing the pipeline of new opportunities which may shape our future asset portfolio.”

The additional funding and expertise aside, Bewick says the selection is a major vote of confidence.

“The connections and what they call the ‘master classes’, where they bring in people at the top of their game to provide training, whether that be in business management, communications, technical programs — they’re bringing in what a company like ours just could not have access to. It’s really hard to value that. It’s a condensed and very aggressive timeline to get everything done, but equally, you’re getting exposed to some fantastic people,” Bewick says.

“No matter what we do at the end of this program, whether it’s something with BHP or not, the project is going to be in a much better state than it was — and would have been — without the Xplor program. It’s a great outcome for us and a tremendous vote of confidence. That a company like BHP is even slightly interested in, or has a good interest in, the West Tanami Project means a company the size of Hamelin should be super fascinated by its potential.”

The road ahead

While the Xplor program is likely to be a major leg up over the next 6 months, it’s Hamelin’s soil sampling prowess which Bewick believes could make the real long-term difference.

“The fact that we’ve managed to link surface anomalies to bedrock gold is a huge positive for the new tool, how it’s going to be applied, and where we can apply it,” he says.

“It’s not a panacea, it’s not a silver bullet that’s going to work in every single terrain. But in this particular environment, with these similar conditions elsewhere, we should be able to do soil sampling in the desert undercover, and potentially find new gold systems.

“I think you’ll see over the next year, our land position will dramatically reduce to just those key corridors we think host a major gold system. And as we narrow our focus in those areas, you’ll see us applying the technology in other areas of the state and we’ll be looking at moving into new projects as well.”

Write to Oliver Gray at Mining.com.au

Images: Hamelin Gold
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Written By Oliver Gray
Originally from Perth, Oliver has a keen interest long-form journalism. He has written for a number of publications and was most recently Contributing Editor of The Market Herald’s opinion section, Art of the Essay.