Southwest Wyoming’s historic Kemmerer coal mine is scheduled to shut down by the end of 2029, according to mine officials. The announcement follows a decade of declining production and the loss of its largest customer, the Naughton power plant, which completed a conversion to natural gas in December 2025.

Mine outlook and workforce

Don Crank, President and Mine Manager for Kemmerer Operations, told WyoFile that the decision reflects “a dynamic business” environment. While the timeline remains subject to change, the current plan does not include layoffs. About 153 miners are employed at the site, with roughly two‑thirds represented by United Mine Workers of America Local 1307, a union that has served the mine for more than a century.

Impact on the soda‑ash industry

The mine has long supplied the adjacent trona and soda‑ash sector, providing daily truckloads of coal to fire boilers and, in some cases, generate onsite electricity. With the mine’s eventual closure, producers such as WE Soda are evaluating alternatives. The Wyoming Energy Authority recently recommended a $13 million grant to help WE Soda build a natural‑gas supply connection, describing the project as a way to “maintain the competitiveness of Wyoming‑produced soda ash” once local coal is depleted.

State response and industry options

Wyoming officials are studying how to assist the soda‑ash sector, which accounts for more than half of the state’s $1.3 billion annual export value and employs roughly 2,500 workers in the southwest corner of the state. A February‑published Wyoming Coal Study noted that two of the five soda‑ash plants in the region consume about 1 million tons of coal each year. The study urged the state to consider extending the Kemmerer mine’s life or developing a replacement local coal supply.

Industry leaders are also exploring third‑party power contracts from new natural‑gas‑fired generation and the potential use of modular nuclear micro‑reactors to replace lost coal‑derived heat.

Historical context

The Kemmerer mine has changed hands several times since its former owner, Westmoreland Coal Company, filed for Chapter 11 bankruptcy in 2018. Ownership passed to PhenixFIN and most recently to ECC Capital Corporation. Production has fallen sharply, from 4.2 million tons in 2017 to 2.4 million tons in 2024 and just 1.5 million tons in 2025, according to federal data.

Looking ahead

While the mine’s future remains uncertain, the transition to natural gas aligns with broader energy trends in the region. The state’s support for infrastructure upgrades aims to safeguard jobs and keep Wyoming’s soda‑ash industry a vital part of the local economy.

Original reporting: Oil City News (Casper WY) — read the source article.