Critical mineral development: Grid Metals promotes southeast Manitoba cesium deposit

An exploration company says it’s found the second-largest cesium deposit to be developed in the Western world — and it’s looking to mine in southeastern Manitoba.

Cesium is used in the defence sector, solar panels, internet and phone networks and GPS satellites, among other things. Canadian and United States governments have both deemed it a critical mineral.

It’s rare: just six cesium deposits have been found globally, according to the company behind the Manitoba site.

Grid Metals, a Toronto-based firm, spent October 2025 through March drilling holes in land 130 kilometres east of Winnipeg, at its Falcon West property.

Some 50,000 tonnes of rock contains about 1,300 tonnes of cesium, said Grid Metals president Robin Dunbar.

He said the deposit is the second largest to be developed by a Western country. The Tanco mine, by Bernic Lake near Lac du Bonnet, is Manitoba’s only cesium-producing mine and one of the world’s largest suppliers.

“You might be able to mine it all in a year,” Dunbar said of the Grid Metals project. “The cesium we have in our resources is roughly equivalent to about half of one year’s global supply.

“It’s not an insignificant amount.”

Cesium isn’t part of a quoted market like gold or copper. Grid Metals would discuss pricing with customers following metallurgy studies, which are happening now, Dunbar said.

He estimates the mineral would net “tens of millions of dollars.”

First, the company must submit an environmental act licence, which it plans to do by the end of 2026.

Grid Metals also needs consent from Sagkeeng First Nation; the project is on the nation’s traditional territory. Consent hasn’t yet been given, said Chief E.J. Fontaine, but talks are ongoing.

“We’ve had a really great relationship with Grid,” Fontaine said. “They’ve been very transparent, very eager to engage Sagkeeng.”

The two parties have connected for at least 3 1/2 years. Two First Nations members have been technicians on Grid Metals’ prospecting team.

Still, there’s a need to hash out details about a mining project — especially environmental concerns and economic benefits, Fontaine said. “It’s time now that Sagkeeng benefits from the resources that are being extracted in our territory.”

The proposed cesium project could be “something big,” said Renee Greyeyes, chief executive of the Manitoba Prospectors and Developers Association. “(It’s) an opportunity for Manitoba to contribute to a more reliable supply of critical minerals.”

China produces much of the world’s cesium.

Grid Metals has partnered with Avenir Minerals on the Manitoba project. Avenir Minerals is a subsidiary of Agnico Eagle Mines Ltd., a multibillion-dollar company and a behemoth gold producer. It has a 15 per cent interest in the project.

The site is accessible by road, some 500 metres north of the Trans-Canada Highway.

gabrielle.piche@winnipegfreepress.com