The company, chaired by former Red 5 managing director Mark Williams, raised A$10 million in its October initial public offering, which was “five or six times” oversubscribed.

Since listing on October 30, the stock is up by around 80% on its A20c listing price – and that’s before the company has even drilled a hole.

“That’s a testament not only to the team and the project, but also to our investors,” Sentinel managing director Matt Herbert told a webinar this week.

The Columbia gold project was vended into Sentinel by Dahrouge Geological Consulting, a well-known Canadian consultancy and project generator that was also behind PMET Resources’ world-class Shaakichiuwaanaan lithium project in Quebec.

Dahrouge is a major shareholder in Sentinel, while geologist Simon Dahrouge sits on the Sentinel board as an executive director.

‘Absolute beauty’

Sentinel is starting from a very solid base at Columbia.

The project already has an inferred resource of 21.4 million tonnes grading 1.3 grams per tonne gold and 4.6g/t silver, or 1.4g/t gold equivalent, for 920,000 ounces of gold or 960,000oz of gold equivalent.

The resource is based on 45,000m of drilling and is constrained by a US$2200 an ounce open pit optimisation shell, well below the current spot price.

“We’re close to a million [ounces] now – I could genuinely add 200,000oz overnight by tightening up some of our constraints,” Herbert said.

“We’ve got ounces we can add through drilling and we’ve got ounces we can add on paper.”

In addition to the resource, the project also has an exploration target of 22-27Mt grading 1.1-1.4g/t gold for 800,000oz to 1.2Moz of contained gold.

Historical drill hits include 3.1m at 106.3g/t gold from 33.5m; 12.2m at 11.6g/t gold from 1.5m; and 132.6m at 2.01g/t gold from 15.2m.

Previous metallurgical test work yielded gravity concentration of up to 56% for gold and 18% for silver from a bulk sample, while gravity tail flotation increased recoveries to 96% gold and 77% silver.

“The asset is an absolute beauty,” Herbert said. “The runs are already on the board – has it got legs? Absolutely.”

‘Open for business’

Columbia sits on private land about 13km from the town of Lincoln via bitumen road.

Herbert said the region had historically produced more than 18Moz of gold.

Montana is known as “the treasure state” due to its history of gold and silver production, dating back to 1852.

While permitting in the US hasn’t always been the easiest, Herbert declared Montana as being “open for business” with 12 permits granted in the past two years, including new mines, expansions, exploration permits and tails re-processing projects.

Three projects in the state have been added to the FAST-41 program for faster approvals in the past three months.

When updating the prefeasibility study this week for its Black Butte copper development in Montana, Sandfire Resources spoke of the supportive environment for projects in the US.

Work ramping up

Sentinel just wrapped up a dual-spaced, high-resolution hybrid-source audio magnetotellurics program, which highlighted regional structures and showed sub-vertical vein-related resistive trends that extended well below previous drilling.

Herbert described the results as “super compelling”.

“It will lead us to what I think is the most exciting drill program in North America in the next quarter of 2026,” he said.

“We have enough targets so we could have gone out and got an application to drill early, but there were some very basic geophysics that hadn’t been done on the deposit.”

Herbert described magnetotellurics as the “gold standard” for low-sulphidation epithermal systems like Columbia.

It also allowed the company to visualise the deeper core of the system for the first time and target possible feeder zones that could host the roots of the system.

It’s given Sentinel strong targets to test in its upcoming 5000m diamond drill program.

“This is about to get exciting,” Herbert said. “The catalysts are coming. The targets are incredibly exciting and we’ve spent a lot of time going through them.”

Despite the large resource, Columbia has only been drilled to around 220m below surface.

“There’s so much depth potential. We expect this thing to coalesce at depth,” Herbert said.

Sentinel expects to be drilling until around March, which will lead into a resource update in around May or June.

“It’s by far the most excited I’ve ever been for a drill program and to put it into perspective, I’ve been drilling holes for 19, 20 years,” Herbert said.