Stillwater Critical Minerals Outlines Path to PEA After Tripling Resource to 805Mt

# Stillwater Critical Minerals Outlines Path to PEA After Tripling Resource to 805Mt

The company published its third resource estimate last week, which CEO Mike Rowdy calls a step-change. Two numbers anchor the update: roughly **805Mt at 0.34% nickel-equivalent** (the bulk-tonnage footprint) and a separate **83Mt at 0.71%** higher-grade zone that Rowdy says could anchor a starter mine. This is the first Stillwater resource that includes any indicated category — proof, in Rowdy's words, that "the model is working." Around 96.5% of the total is still inferred.

## A bigger footprint, a more credible one

The deposit sits in the lower Stillwater complex, which Rowdy describes as the third-largest layered magmatic system in the world (the other two are in Africa). Stillwater Critical Minerals' ground is contiguous with Sibanye-Stillwater's Montana mine along the full 33-kilometer project length, and the peridotite host (the ultramafic rock that hosts the nickel-copper-PGE mineralization) runs a kilometer thick just south of Sibanye's workings.

The new estimate consolidates what were previously five deposits into four, with CZ and Central now merged. Drilling, Rowdy says, shows HDR is "very close" to the merged CZ-Central block — hinting that a future update could join three of the four deposits. Chrome Mountain and Iron Mountain remain separate, with about six kilometers between them.

## Grade matters as much as tonnage

Rowdy repeatedly emphasizes that Stillwater is not a homogenous low-grade body. Within the resource there are three grade bands — 0.5%, 0.35% and 0.2% nickel-equivalent — with implied gross rock values of up to $130 per tonne in the high-grade scenario and around $60 per tonne in the lower one. He says each band "will support a lot of mining methods," leaving the eventual cut-off grade to the engineering studies.

## PEA next, PFS later

Rowdy is explicit that the next milestone is a Preliminary Economic Assessment (PEA — an early-stage study that scopes whether a deposit could support a mine), not a Pre-Feasibility Study (PFS — a more rigorous, indicated-resource-based economic study). A PEA does not require indicated resources; a PFS does. With this resource out, the company's focus shifts from expansion to "definition upgrading" — converting inferred material into indicated to support later studies.

Internally, Rowdy says the team is starting to think about a PEA that presents two cases — a high-grade starter option and a bulk-tonnage alternative — though he declines to confirm that publicly. He expects the PEA "next year," with metallurgy work as the rate-limiting step.

## Metallurgy and the chromium question

Two metallurgy streams are running in parallel:

- **Conventional flotation**, drawing on earlier bench-scale work by AMACS on the CZ (CampZone) deposit, which produced a saleable concentrate in single-stage testing at roughly 85% recovery. Glencore's XPS flotation group is in the conversation. - **Hydrometallurgy (hydromet)**, pursued with Columbia University, intended to unlock broader recoveries from a cruder on-site concentrate and feed a US domestic supply chain that Rowdy argues currently has no domestic nickel smelter.

Chromium is the swing factor. The resource contains roughly 6.6 billion pounds of inferred chromium and 0.222 billion pounds in the indicated category. Rowdy notes Stillwater is essentially the only source of chromium at scale and grade in the US — historically subsidized for chrome production in the 1940s and 1950s — but the company has not yet assumed any economics or recovery for it. The base case for the PEA will be "conventional thinking," with hydromet and chromium framed as upside rather than core.

## Why Sibanye's losses matter

Sibanye-Stillwater is operating right next door. Rowdy cites Sibanye's US PGE AISC (All-In Sustaining Cost — what it really costs to produce an ounce) at around $1,300 per ounce and says the company is "losing money at that." By contrast, he points to the Platte Reef mine in South Africa's Bushveld complex at roughly $599 AISC per ounce as the cost profile Stillwater's broader, multi-mineral resource could support.

Rowdy sees the gap as strategic optionality. Stillwater could be a takeover target, a joint-venture partner, or, in his own words, "the economic upside" for Sibanye if Sibanye decides the US operations are no longer a core asset. He notes Sibanye itself said on its latest call that it is trying to bring US costs down to $1,000 per ounce, and that South African gold operations are currently subsidizing the PGE mines.

Glencore is also engaged. Rowdy describes Glencore as "very engaged" at both the technical committee and corporate level, with a site visit planned later this month. He does not rule out a JV or a counter-acquisition scenario where Stillwater takes over Sibanye's Montana operations.

## Funding and the next 12 months

The company raised $17 million at the end of last year and reported $15 million in the bank on its last financials. Three rigs are currently turning in Montana, with smaller programs in the Yukon and a gold asset held through Heritage Mining in Ontario. Rowdy expects to run more rigs next year, with the bulk of near-term spending on drilling ahead of the PEA. Government engagement continues across the county, state and federal levels — including a recent DOW event presentation — where Rowdy says the project's 10 critical minerals and historical district status have drawn consistent interest.

The 12-month plan, as described: more drilling, metallurgy work, government updates, the PEA itself, and ongoing conversations with Glencore and Sibanye about the longer-term structure of the asset.