While exploring historical mining districts is not a new concept, there are some previously picked over jurisdictions around the world that are starting to witness a modern-day exploration resurgence.
In the words of Marc Branson, CEO of Canadian uranium and critical minerals explorer Dark Star Minerals (CSE:BATT), “It’s always easier to find things where they’ve been found before.”
“It’s a lot easier to know there’s a 300,000-ounce deposit and take it to 3 million ounces than just start poking holes in the middle of nowhere and hope to find one,” he tells Mining.com.au.
“As simple as that is, it’s usually because of the geological settings that these regions became important in the first part.”
Dark Star’s Bleasdell Lake Uranium Project in northern Saskatchewan, Canada has seen extensive historical exploration that uncovered a uranium deposit and a non-compliant resource of 620,700 pounds of the nuclear fuel.
The work was primarily undertaken in the 1950s and centred on the Horn and Jackpine zones.
Nearly 150 holes were drilled reaching depths of 22.9m to just shy of 150m for total drilling of roughly 3,750m.
The Horn zone was initially defined over 300m in length and around 7-9m wide.
A report was prepared in 1957 for previous explorer Columbia Metals Exploration that noted the potential of the project, stating: “The Bleasdell prospect is well positioned for economic development.”
Dark Star notes that at the time, uranium was just US$7.50 ($11.46) per pound.
Besides a substantial rise in the uranium price since then, exploration in northern Saskatchewan had petered out for some time because of the depth of these deposits.
“A lot of the stuff, especially in northern Saskatchewan, that they’ve been looking for is … usually pretty deep, fairly large obviously and high grade, but deep and pretty expensive to put into production,” Branson explains.
Surface ounces cheaper, faster to mine
He notes that Bleasdell is a little bit different to the typical deposits in the area, in that a smaller, near-surface resource could potentially be defined more quickly and cost effectively.
“It’ll be interesting to see what results we get because if it does pan out the way we think, it’s a couple of million dollars in drilling to probably get it to a couple of million pounds of resource, which is small but being at surface you can put it in production right away,” Branson says.
Dark Star is planning to undertake follow up exploration focused on the historically drilled Horn and Jackpine zones because they are known for hosting uranium-bearing pegmatite zones.
The company’s Ghost Lake Project in the Central Mineral Belt in Labrador is less explored than the Bleasdell Lake Project because of the introduction of a three-year moratorium on uranium in 2008.
“There was a lot of money spent in that area and then when the moratorium came in uranium also went through a bit of a lull,” Branson says.
“So it kind of killed everybody’s ambition to be in there. The moratorium got lifted and then lo and behold nobody wanted to do any uranium exploration. So the area went dead for quite a while.”
Ghost Lake sits along trend from Paladin Energy’s (ASX:PDN) 128-million-pound Michelin Deposit, which is one of the largest uranium deposits in North America and has witnessed $75 million worth of total in-ground exploration so far.
Branson says balancing underexplored ground versus historically explored ground is based on risk versus reward.
“It’s going to come down to a risk-reward scenario in which obviously there’s geological pointers like soil samples … or some sort of structural fault,” he says.
“You’re not going to go in and spend a lot of money without it being a very large find. Whereas stuff that actually has some history to it and has some pounds in the ground, you’re kind of more apt to just continue to push it along.”
“Stuff that actually has some history to it and has some pounds in the ground, you’re kind of more apt to just continue to push it along”
Waking sleeping giants
Meanwhile, Rua Gold (TSX-V:RUA) is looking to play a key part in reawakening New Zealand’s past producing Reefton Goldfield, located on the country’s South Island.
The Reefton district historically produced over 2 million ounces at grades of between 9 and 50 grams per tonne.
Rua said in July the goldfield was seeing a resurgence in interest, led by the construction of the Blackwater mine, which is owned by private firm Endura Mining — formerly Federation Mining — and expected to enter production in 2026 producing 65,000 ounces each year.
The company owns 95% of the land surrounding Endura Mining’s operations.
Rua also has a foothold in a second gold district in New Zealand – the Hauraki Goldfield on the North Island which historically produced 15 million ounces of gold and 60 million ounces of silver at grades of between 15g/t and 30g/t.
Reefton, nicknamed ‘The Town of Light’ because it was the first town in New Zealand and the southern hemisphere to have a public electricity supply and electric street lighting, was the site of a gold rush that started in the 1860s.
CEO Robert Eckford told Mining.com.au in August that exploration and mining came to a standstill around the 1950s and there has not been a “decent exploration campaign” since then.
“It stopped only because they didn’t have the technology to go to the depths that we have underground mines today,” he said.
“So, you’ve got these shallow historical underground mines, the deepest they go to is around 500-600m and they’ve never been explored under that.
“That’s the opportunity here, you’ve got an entire district-scale play – 120,000 hectares – and you know there’s gold there already, it’s just a question of how much gold is left.”
Mining investment in New Zealand in previous years has been hindered by the anti-mining stance of the former government.
However, Resources Minister Shane Jones – who refers to himself as a “pro-mining minister” – this year launched New Zealand’s first ever Critical Minerals List and named the Reefton Goldfield as one of the key focus points of the critical minerals strategy.
Oregon ‘open for business’
Provenance Gold (CSE:PAU) is revisiting an historically explored area in Oregon known as the Eldorado Project, which has a pre-existing non-compliant resource of 2 million ounces.
The company is working to bring that resource into NI-43-101 compliance and Chairman Rauno Perttu believes even with the existing 2 million ounces there is still further significant growth potential.
“It’s a wide open system,” Perttu tells Mining.com.au. “I think, in my personal opinion, it’s going to go over 10 million ounces.”
In early May, Provenance increased the size of the Eldorado Project after staking a further 18.33km2 of ground and securing an option agreement covering two historical mines, creating what the company calls a “district-scale opportunity”.
“What is special about the new acquisition is that it is the most intensely historically mined by lode mines and placer mines of any area that I’ve seen in Oregon. In fact, in almost any area I’ve seen anywhere,” Perttu explains.
“Some of the valley areas, where there’s very little exposure, have been placer mined two or three times, suggesting the amount of gold in the system.”
Placer mining is the mining of stream bed deposits using simple methods like panning or more intensive methods like dredging or excavation.
Oregon only very recently became “open for business” again, after US President Donald Trump added Paramount Gold Nevada’s (NYSE:PZG) Grassy Mountain Gold Project to the US Government’s Federal Permitting Dashboard.
Known as ‘Fast-41’, the program is a legislatively established process for improving federal agency coordination and the timeliness of environmental reviews for key infrastructure projects.
Provenance Gold revealed last week that all 10 holes drilled in the company’s 2025 reverse circulation drilling program intersected gold mineralisation.
The explorer is targeting bulk tonnage areas within the Tyee area.
Explorers follow trails left by pioneers
Meanwhile, Vertex Minerals’ (ASX:VTX) Hill End Project in New South Wales was the site of the discovery of the largest gold specimen ever found globally — discovered by Bernhardt Holtermann in 1872.
It was the largest non-alluvial nugget ever mined weighing in at 268kg.
Vertex has identified multiple targets across 34km of strike of the same structure determined to be the source of the gold specimen.
A previously completed Lidar survey uncovered over 3,500 surficial gold workings over the line of the lode. Just 800m of the total strike has been drilled and only down to a few hundred metres.
“Old timers mined the full 30km length of Hill End tenements for 3500+ workings and they only scratched the surface. This is a big system,” Vertex says.
The Hill End and Hargraves Project, which sits about 40km from Newmont’s (NYSE:NEM) Cadia gold operation in the Lachlan Fold Belt of New South Wales, historically produced 1.8 million ounces of gold.
Dart Mining (ASX:DTM) has also uncovered historically significant areas on its ground in Queensland.
The company’s Coonambula Project, which is being explored under an earn-in deal with Great Divide Mining (ASX:GDM), hosts the historical Banshee Antimony Mine.
Previous drilling intersected high-grade antimony and gold mineralisation over a 650m strike length, including 3m @ 9.18% antimony, 3m @ 1.5% antimony and 8.53g/t gold from 18m, and 6m @ 5.12% antimony and 1.55g/t gold.
The Coonambula project is located 130km from Dart’s Triumph Gold Project, which the company only recently discovered had a previously forgotten past-producing antimony mine.
Geological fingerprints reveal overlooked opportunities
Executive Chairman James Chirnside told Mining.com.au in August that the discovery was a bit of good luck for Dart, with the previous owners not having really looked at it.
“The old antimony mine is on the Queensland geology maps, but there’s no information. We understand the workings were significant, and there’s one or two historical references in newspapers indicating that,” he says.
The Triumph project has an existing inferred resource of 150,000 ounces of gold @ 2.17g/t, with over 85% of the resource within 100m of surface.
“We’ve only exploited about 20% of the known strike but some of our recent drilling is pointing to significant additional zones of mineralisation and high-grade depth potential,” Chirnside said.
“We’ve got two corridors that we’re drilling and exploring and potentially a third corridor.”
Canadian explorer Signature Resources (TSX-V:SGU) is advancing its Lingman Lake Project in the prolific Red Lake District of Ontario.
However, Lingman Lake has witnessed only sporadic historical exploration because of its remote location, according to CEO Dan Denbow.
“If this project was within one of the existing mining districts it would have 10 times the amount of exploration work and would already be heading towards production,” he tells Mining.com.au.
“But being remote it has had inconsistent exploration activity over 80 years due to location and gold price cycles.”
At the end of July, Signature Resources released a maiden gold resource for Lingman Lake of 2.15 million tonnes @ 1.38g/t for 95,200 ounces in the indicated category and 18.4 million tonnes @ 1.14g/t for 674,320 ounces in the inferred category.
Last year, geological consultant Watts, Griffin & McOuat updated the geological model to incorporate drilling completed in the 1980s which further expanded the high-grade mineralisation zones.
It also identified moderate grade mineralisation between 2g/t and 5g/t that had not been a focus of past efforts despite being less than 200m from surface.
Denbow says Signature’s exploration work has proven that Lingman Lake is a worthy gold property and a profitable starter pit opportunity.
“We believe the resource can be quickly expanded with a reasonable exploration effort,” he says.
Historical goldfields eyed for fresh riches
Another Canadian explorer, Cassiar Gold (TSX-V:GLDC), has a large presence in two major past-producing gold districts in British Columbia.
The company’s flagship asset is the Cassiar Gold Project, which spans a 590km2 district-scale orogenic gold system and historically produced 350,000 ounces of gold. It comprises five historical mines.
The Cassiar South prospect hosts several high-grade quartz gold vein systems, 25km of historical underground workings, and prospects over 9km of strike.
The project has historical infrastructure in place, including a permitted 300-tonne-per-day mill, tailings facilities, 160km of access roads, a 48-person camp with grid power and water and established mine permits.
Cassiar also controls British Columbia’s third largest past-producing inland orogenic gold district. The Sheep Creek Project is a 42km2 camp that has had minimal exploration since mining ceased in the early 1950s.
The mines in the district produced 742,000 ounces of gold, 365,000 ounces of silver, 377,000 pounds of lead and 312,000 pounds of zinc from 1.72 million tonnes of ore from 1899 to 1951.
Gold-bearing quartz veins were first discovered in the Sheep Creek area in 1896 and led to staking of the initial claims to cover the Yellowstone and Queen veins.
Limited production in the Sheep Creek camp began in 1900 with the development of the Yellowstone mine, followed by the development of the Queen mine.
Additional discoveries of auriferous veins were made in 1904-1905 and led to the development of the Kootenay Belle, Nugget and Motherlode mines by 1911.
The Reno vein, discovered in 1912, was the last significant discovery made in the Sheep Creek gold camp, but became its most productive mine.
Since the early days of discovery, surface work and an estimated 65km of underground development has identified about 60 to 70 veins over a roughly 8km north-south trend.
The past-producing mines hosted within Cassiar Gold’s Sheep Creek property are responsible for about 84% of the camp’s total historical production.
A 2017 Geoscience BC report highlighted that veining at Sheep Creek is analogous to that in the Barkerville area – the second largest past-producing orogenic gold district in British Columbia.
Another company revisiting historically explored North American ground is Astute Metals (ASX:ASE).
The company’s Needles Gold Project in Nevada is underexplored and host to eight historical mines dating as far back as the 1800s.
Old timers got hands dirty for success
Healy told Mining.com.au in a prior interview that all of these mines would have been dug by hand back in the day.
The largest mine is known as Arrowhead, which extends down to 110m.
“There are four levels in this mine,” Healy said. “They did not do that sort of thing just for fun, they did it for really high-grade ore.”
Rock chip results taken from waste piles near the mine yielded grades of up to 1,115g/t silver and 2.57g/t gold.
Drilling along strike from the Arrowhead Mine returned intercepts including 3.42m @ 905g/t silver and 2.92g/t gold.
Past drilling is mostly shallow, and alteration mineralogy and pathfinder geochemistry suggests that this drilling is high up in the ‘cap’ of the epithermal system, indicating the most prospective exploration space is yet to be tested.
AngloGold Ashanti’s (NYSE:AU) 16-million-ounce Silicon-Merlin gold discovery, uncovered in 2018, also features this upper cap alteration zonation, with drilling undertaken beneath historical drill holes highlighting the potential for major epithermal gold discoveries in Nevada.
“They targeted some faults at depth below all of the historical drilling and on the second hole they made the discovery,” Healy said.
Astute’s Needles Project also features the same host rocks as the 20-million-ounce Round Mountain Mine, located 100km to the north.
Victoria’s Golden Triangle still hides treasure
Over in Victoria, Aureka (ASX:AKA) and North Stawell Minerals (ASX:NSM) are both focused on uncovering more gold in historically mined areas of the Stawell district.
The Stawell goldfield dates as far back as the 1850s, when William McLachlan found gold in cement – ancient river gravels cemented together into a very hard conglomerate – in the bed of Pleasant Creek in May 1853.
According to the Victorian Government, a gold rush followed in the winter of 1854.
Aureka says its Stawell Corridor Project – which incorporates the Irvine and Langi Logan gold projects and five other prospective targets – captures 60km of a multi-million-ounce gold zone.
Irvine, which hosts an inferred resource of 304,000 ounces @ 2.43g/t gold, sits on the margins of a basalt dome about 20km from the operating 5-million-ounce Stawell Gold Mine, while Langi Logan has been the site of significant historical deep lead gold production in local areas.
Deep lead mining is a distinctive feature of the goldfields in Victoria, according to AusIMM, which says it is estimated that about 265,000 kilograms of gold was produced from deep lead mines.
This process of mining involves extracting gold from ancient buried riverbeds and was largely done between the mid-1880s and early 1900s.
North Stawell Mines, meanwhile, is exploring for shallow repeats of the multi-million-ounce gold deposits at Stawell on the margins of other basalts under cover.
The company holds ground spanning 60km of a geologic fault where it continues to the north, but 85% of the ground is masked by a thin blanket of unmineralised sediment – or cover as it is also referred to – that starts just 6km north of the Stawell Gold Mine.
This cover was an “impossible barrier” to historical prospecting but modern-day exploration can now target what is below with geophysics and drilling, according to CEO Campbell Olsen.
The Stawell Corridor forms one of the vertices of Victoria’s Golden Triangle.
Resources Victoria says the state has 13 goldfields that have each produced more than 1 million ounces of gold. The 22-million-ounce Bendigo goldfield is the largest, followed by Ballarat, Castlemaine, Stawell and Woods Point-Walhalla.
The Geological Survey of Victoria estimates that there may still be up to 75 million ounces of gold to be found in the northern parts of the Stawell, Bendigo and Melbourne zones, including multiple million-ounce occurrences.
Write to Angela East at Mining.com.au
Images: Mining.com.au, Dark Star Minerals, Rua Gold, Provenance Gold, Wikimedia Commons, Signature Resources
