Strike Halts Part of America’s Only Platinum Mine

Part of America’s only primary platinum and palladium mining complex went quiet this week. On September 3, roughly 420 members of United Steelworkers Local 11-0001 walked off the job at Sibanye-Stillwater’s Stillwater East mine and Columbus metallurgical complex in southern Montana, after more than four months of contract talks broke down over healthcare and disability benefits.

At a glance

• The strike began at 7 a.m. Mountain time on September 3, 2026, two days after the union gave formal notice.
• About 420 workers at Stillwater East and the Columbus metallurgical complex are affected; the nearby East Boulder mine, covered by a separate contract, is not on strike.
• The dispute centers on a proposed family health deductible rising from $500 to $1,400 by 2029 and a cut to long-term disability coverage.
• Stillwater East and East Boulder together produced 137,930 ounces of platinum and palladium in the first half of 2026, the only primary supply of either metal mined in the United States.
• Negotiations had run since mid-April 2026; workers rejected the company’s contract offer three times before Sibanye-Stillwater implemented its final proposal and the union struck.

Why did the union call a strike now?

United Steelworkers Local 11-0001 represents workers at Stillwater East and the Columbus complex, and its members rejected Sibanye-Stillwater’s contract offer three separate times over the summer before the company moved ahead with its own final terms. The sticking points are benefits, not base pay: the company’s proposal raises the family health deductible in steps from $500 today to $1,400 by 2029, and would trim long-term disability coverage from 180 days at full pay to 90 days at 80 percent followed by 90 days at 67 percent. Underground miner Andrew Cameron told Montana Free Press, “We aren’t asking for anything more than what we’ve had. We’re fighting for the same benefits we’ve had for years,” pointing to the physical risks of underground mining as the reason the existing coverage matters.

Sibanye-Stillwater frames the changes differently. The company says its Montana operations spend roughly $30 million a year on employee healthcare, well above typical industry benchmarks, and that current operating margins leave little room to keep costs rising on the current path. In its notice, the company said reducing unit operating costs at the US operations remains essential to the long-term future of the mines, and that modernized work practices and a redesigned incentive plan are part of that effort.

What is at stake for America’s only platinum and palladium mines?

The Stillwater Complex south of Columbus is the only place in the United States where platinum and palladium are mined as primary products, metals used in catalytic converters, electronics, and a range of industrial processes that otherwise depend on imports from South Africa and Russia. Stillwater East alone produced 76,334 ounces in the first half of 2026, roughly 55 percent of the complex’s combined output and about 446 ounces a day. A prolonged strike does not touch that daily production rate directly, since idled work simply is not being done, but it does interrupt underground development and maintenance that future output depends on. East Boulder, covered by its own agreement, continues operating and is not affected by this strike notice.

Montana’s mining identity runs through both hard-rock metal and hard labor history, from the Anaconda-era copper fights on Butte’s Richest Hill to this newer chapter at Stillwater. Our Montana master report and the Butte tour stop cover how the state’s mines, past and present, fit into that longer story, and our earlier coverage of Sibanye-Stillwater’s palladium trade fight covers the same operation’s exposure to Russian import competition.

What happens next in the Stillwater dispute?

Neither side has set a timetable for a return to the table. Sibanye-Stillwater says it remains committed to reaching an agreement that protects the operations’ long-term viability, while the union has not signaled a change in position on the deductible or disability terms. Production continues at East Boulder in the meantime, and how long the affected Stillwater East and Columbus workforce stays off the job will determine how much of this year’s development schedule slips at America’s only primary source of platinum and palladium.