Site visit: Inventus advances continent’s sole paleoplacer gold project near Sudbury

Sudbury, Ont. – Inventus Mining’s (TSXV: IVS) Pardo gold project might be the largest of its kind in North America and the latest surprise to come out of the geological hotspot of the Sudbury region.

For the Eric Sprott and McEwen-backed (TSX, NYSE: MUX) explorer, Pardo stands out as a paleoplacer project, a type of alluvial deposit that sits relatively close to the surface, and potentially costs less to mine than most open pit or underground deposits. Pardo is a 90-minute drive from Sudbury, 65 km to its east.

“The cost of mining is extremely cheap, and not only the cost of mining, but any reclamation of the land as well,” Inventus CEO Wesley Whymark told The Northern Miner during a July site visit.

“Even during the construction period…you can direct ship the ore to a third-party processing facility, and if you’re making money doing it then you’re not so reliant on capital markets to provide the necessary capital.”

Watch a video of the site visit

 

Success at Pardo would introduce a style of gold deposit that has produced some of the world’s largest gold mines but has never been developed in North America after Pardo was overlooked in the Sudbury region amid the rush to mine copper and nickel over more than a century.

Paleoplacer gold promise

Unlike the placer gold deposits in Yukon that fuelled the Klondike rush, paleoplacer deposits are slightly deeper and much older. Over billions of years, their yellow metal deposits were consolidated into hard rock rather than spread among gravel and stones of riverbeds.

Pardo’s possible peers include Pan American Silver’s (TSX, NYSE: PAAS) Jacobina mine in Brazil, which has produced 2.8 million oz. of gold since 1983; and dozens of mines in South Africa’s Witwatersrand Basin that have produced more than 1.5 billion oz. of gold since the late 1880s. The Tarkwa mine in Ghana, now operated by Gold Fields’ (JSE, NYSE: GFI) has produced more than 10 million oz. since the 1870s.

But the deposits at Jacobina and Tarkwa are angled and go deep, Whymark said, making them more challenging to mine.

“We’re just fortunate here at Pardo that the deposit is still flat and wasn’t subject to any faulting or folding,” he said.

Sudbury overshadowed Pardo

While the Sudbury Igneous Complex produced 30 million tonnes of nickel and copper since 1886, the neighbouring Huronian Supergroup package of sedimentary rocks was deemed uneconomic decades ago, Whymark said. The exception was the paleoplacer uranium discovered in Elliot Lake in the 1950s.

“This led to a search for more uranium throughout the Huronian basin, and that exploration work was never assayed for gold,” he said. “The entire eastern part of the Huronian, where Pardo is located, was withdrawn from staking in the 70’s until the late 90’s.”

Endurance Gold (TSXV: EDG; US-OTC: ENDGF) discovered the Pardo paleoplacer deposit in 2007 and advanced it through drilling before optioning it to Mount Logan Resources in 2009. Ginguro Exploration acquired Logan and eventually changed its name to Inventus Mining in 2015.

Spying for gold

Whymark leads the site tour into the wide 007 pit bounded by two high walls of outcrop and the remains of blasted rock on the other sides. Inventus gave the pit that name after the nephew of James Bond creator Ian Fleming bought company shares several years ago.

Pardo’s main Trench 1 and 007 pits host very shallow mineralization for a gold project.

“The grade control drill holes that define those pits were about eight meters deep, and the zone was about two meters thick,” Whymark said. “It was within six meters of surface.”

Beyond its shallow depth, mining Pardo would be much like any other underground or open pit site in that ore is blasted, crushed and hauled to a mill. Inventus has already been sending crushed ore for bulk sampling to McEwen’s Stock mill in Matheson, about 200 km northwest of Pardo.

Those samples were sourced from what Whymark calls the “main layer” at Pardo that’s about 2 metres thick grading about 2 to 3 grams gold per tonne and up to 8 grams gold.

Narrow and shallow

While results from the company’s stage two, 7,000-metre drill program have returned strong grades, they tend to occur in much narrower intervals than in hard rock orogenic gold deposits that represent most gold projects in Canada.

An example is the results from hole PD-26-297 in early July, which cut 2.43 metres grading 2.82 grams gold from 20 metres depth in the Matinenda layer, including 4.27 grams gold over 1.43 metres and 10.51 grams gold over 0.5 metres. 

“We’re drilling and expanding the footprint and determining how far and how thick these layers can be,” Whymark said.

The current drill program is to also support an initial resource for Pardo, expected to be released in the fourth quarter.

$2.3M from bulk sampling

Meanwhile, the returns from Inventus’ ongoing bulk sampling program are already helping to recover costs. Bulk sampling from the 007 North target alone produced 427 oz. grading 3.04 grams gold, yielding $2.3 million and covering $1.2 million in costs.

“The gold value from one bulk sample actually helped pay for the entire next bulk sample, and a little bit of extra cash on top,” Whymark said. “Once we scale that, the margins will get even better and it’s essentially self-funding.”

For the remainder of the bulk sampling program, Inventus plans to process 10,000 tonnes of stockpiled material and extract another 20,000 tonnes of permitted ore.

Bulk sampling could also help finance a stage-three drill program, planned to start later this year. Inventus might release a preliminary economic assessment (PEA) later next year, though Whymark said the bulk sampling program has already significantly de-risked Pardo.

“It’s worth putting a PEA out just to state those realistic numbers,” he said.

Looking underground

It’s early days, but the company ultimately envisions building an underground mine and an on-site processing facility if mineralization at depth is proven. For now, Inventus is working to obtain permits to transition from bulk sampling to mine production as drills to define a larger system that might host up to 2 million oz. of gold, Whymark said.

“[Paleoplacer deposits] can be very big, and we’ve got the only one in North America, and it’s at a stage where we don’t really know how big it could be, and it’s going to take a lot more exploration, a lot more drilling to define how big this system is going to be.”

Rob McEwen holds a 16% stake in Inventus and Eric Sprott holds 15%.

Inventus shares traded for 23¢ apiece on Tuesday in Toronto, valuing the company at $50.8 million. The stock has traded in a 12-month range of 18¢ to 38¢.