57,000 Metres of Drilling Push IAMGOLD's Nelligan Gold Deposit Deeper in Quebec

Gold has now been followed past 600 vertical metres at Nelligan, a deposit about 60 kilometres southwest of Chibougamau, Quebec. IAMGOLD Corporation published the assays on October 27, 2026, together with results from two neighbouring deposits it has drawn into one district.

The release covers about 57,000 metres of diamond drilling done between June 2025 and June 2026, with Philibert drilled from January 2026, split almost evenly between the three deposits. They sit within a 15-kilometre radius, and IAMGOLD now calls them the Nelligan Mining Complex.

Three deposits, two kinds of gold

The complex matters because of its size: the three deposits carry more than ten million ounces of estimated resources between them, and they are different kinds of mine in waiting.

IAMGOLD is an intermediate gold producer based in Canada. It runs Côté Gold and Westwood in Canada plus Essakane in Burkina Faso, according to the release. Nelligan and Philibert are large, lower-grade deposits that the company models as open pits. Monster Lake is small and rich, and it is modelled as an underground mine.

A mineral resource is the company's formal estimate of the tonnes and grade in the ground that have a reasonable prospect of being mined. Indicated resources are drilled closely enough to support mine planning. Inferred resources rest on wider spacing and carry more uncertainty; the release itself says they may never be upgraded. Grade is given in grams of gold per tonne of rock, written g/t.

The estimates in force are dated December 31, 2025.

Added together, the three estimates hold about 4.1 million indicated ounces and about 6.8 million inferred ounces. The inferred share is the larger one, and most of the 2026 drilling at Nelligan and Philibert was aimed at it.

Nelligan keeps going down plunge

The headline claim in the release is about depth. The 2025 and 2026 programmes extended the Nelligan deposit further down plunge to the east, below 600 metres vertical, the company said. Plunge is the direction in which a mineralised body dips into the ground along its length, so drilling down plunge follows the gold deeper and further along at the same time.

The longest interval was 77.0 metres grading 2.23 g/t gold, starting 692.0 metres down the hole.

It came from hole NE-26-272 in Zone 36, one of the deposit's main mineralised zones.

In the Renard zone, which the company says remains open at depth, one hole cut 37.28 metres at 3.62 g/t.

The Footwall zone returned the highest-grade Nelligan interval among the highlights, 7.5 metres at 14.37 g/t.

Those grades sit well above the deposit's 0.95 g/t indicated average. The company makes that comparison itself, saying several intersections grade well above the current resource average. A single hole at twice the average does not lift the average of 122 million tonnes. A run of them at depth, in the same structure, is what extends a pit shell or justifies an underground study beneath it.

The release also flags a gap in the earlier drilling. Zone 36 may extend further south below the 300 to 350 metre vertical level, where it was not systematically drilled, according to IAMGOLD.

Monster Lake runs at a different order of grade

Monster Lake is where the high grades are. The best interval in the release came from the Megane zone: 7.3 metres at 49.6 g/t gold, including one metre at 155.6 g/t.

That hole is shallow. Its interval starts 32.0 metres down the hole, according to the release's drill table. Two more Megane holes each returned around ten metres above 20 g/t.

Two older holes test the zone at depth. One cut 7.7 metres at 24.77 g/t, starting 760.0 metres down the hole.

The other cut 7.5 metres at 10.52 g/t from 853.6 metres. The company says it is evaluating an exploration ramp from surface so it can drill the deeper zone from underground, and that drilling will continue at depth and along strike where hole spacing is too wide.

Grades at this level are measured against a different yardstick from Nelligan's. Monster Lake's own inferred resource averages 14.8 g/t. Several of the new intervals run above that, over widths of five to twelve metres.

Philibert's first full programme

Philibert received the most holes. IAMGOLD now owns all of the deposit, the release says, and 2026 was its first programme there.

Its 65 holes in the release tables, 18,309 metres in all, were drilled from January to June 2026. The company later raised the planned 2026 programme to 30,000 metres and had drilled about 28,000 by the end of the third quarter, so the tables cover the first part of that total.

Most of the work was infill, which means drilling between existing holes to tighten the spacing so that inferred tonnes can be reclassified as indicated. The Red Fox zone returned intervals such as 20.5 metres at 2.51 g/t in hole PB-26-533.

In the Arctic Fox zone, a deeper hole returned 29.3 metres at 3.39 g/t from 468.1 metres down the hole. The company called its two deeper Arctic Fox holes very encouraging.

Where each interval starts in the hole

The highlight bullets give width and grade only, so the starting depth of each interval has to be read from the release's three drill tables. Every assayed interval in the three tables carries a From and a To column, measured in metres down the hole, along with a separate true-width figure. Holes that were abandoned, returned nothing significant or are still awaiting assays carry no interval. Hole ML-26-319 is one of the last group.

True width is the thickness of the mineralised zone measured straight across it, while the core length is simply the length of the hole that passed through it. A hole that crosses a zone at an angle records a longer core length than the zone's real thickness. Across the three deposits the company estimates true widths at roughly three quarters to almost all of the core length. For NE-26-272, the table gives 70.14 metres of true width against 77.0 metres of core.

Three laboratories in Val-d'Or ran the assays, each accredited to the ISO/IEC 17025 laboratory standard, using fire assay and other methods suited to the gold, according to the release. Core was sawn in half on site, with one half kept and the other sent for analysis. Nelligan intervals were calculated with a 0.50 g/t lower cut and uncapped assays. Marie-France Bugnon, IAMGOLD's vice-president of exploration, reviewed and approved the release. She is a qualified person under the Canadian disclosure standard known as NI 43-101.

Drill results and counted ounces are two different stages

The release extends a mineralised system. It does not change the resource, and the company frames it that way.

An extension shows gold continues where it had not been drilled before. A resource estimate is the step that turns enough of those holes, at close enough spacing, into tonnes and ounces that pass an economic test. IAMGOLD says the Nelligan and Philibert results are being incorporated into the deposit models and will support updated mineral resource estimates targeted for the end of 2026. At Nelligan the 2026 work focused on converting inferred resources to indicated, and deeper step-out drilling is being considered for 2027.

That distinction sets the scale of the news. The October 27 holes show the system is larger than the 2025 drilling had defined. How much of it becomes resource, and at what grade, is the year-end estimate's job.

The producer behind the exploration budget

IAMGOLD runs this programme as a producer with operating mines. Côté Gold, the open-pit mine in which IAMGOLD holds 70 per cent, produced 64,400 attributable ounces in the third quarter of 2026, the company said on October 21.

IAMGOLD expects Côté to finish 2026 at the lower end of its 270,000 to 310,000 ounce attributable guidance, with a stronger fourth quarter.

IAMGOLD will report full third-quarter results on November 5, 2026, according to the same release. Those statements will carry the cash and spending figures that sit behind this programme.

IAMGOLD shares closed at C$23.97 on October 27, up 4.58 per cent, per end-of-day data read at 14:02 Pacific on October 27.

Volume on the TSX came to 1,391,257 shares. At that close the company was valued at about C$13.6 billion. IAMGOLD shares also trade in Frankfurt under the symbol IAL, with WKN 899657 and ISIN CA4509131088, according to Deutsche Börse.

The metal sets the backdrop. Spot gold was quoted at US$4,060.30 an ounce at 3:15 p.m. New York time on October 27, 2026, according to Kitco. The October 27 release gives no gold price assumption for the three resource estimates, so the price says nothing yet about which of these ounces would pay. That test belongs to the economic study that follows the resource work.

The company's case, and its scale

Renaud Adams, IAMGOLD's president and chief executive, framed the result in the release as the payoff of consolidation. "Through the consolidation of Nelligan, Monster Lake and Philibert, we have created one of Canada's largest pre-production gold camps," he said.

The drilling supports the first part of that case. Three deposits now have current-year assays and one owner working to a shared timetable. Nelligan has a deeper footprint than it had a year ago, and Monster Lake is returning intervals above its own resource grade. My own assessment is narrower than the chief executive's language and close to it in direction: this is a real expansion of a large system whose size in ounces will be set by the year-end estimates.

Adams said the company looks forward to its next exploration update in the first half of 2027, followed by a preliminary economic assessment of the complex. A preliminary economic assessment is the first study that sets a mine plan and its costs against the resource at an assumed gold price. Capital cost, operating cost and permitting for the complex are not set out in the October 27 release; those are the questions that study is meant to answer.

The next dated step is the updated Nelligan and Philibert resource estimates, targeted for the end of 2026.