California-based Brimstone is advancing plans to establish the first alumina refinery in the US in more than five decades, which is a major step toward restoring the domestic aluminium supply chain. The company has signed a letter of intent with Oklahoma’s Dolese Bros. Co. to supply raw material for the proposed Rock Refinery, which will co-produce smelter-grade alumina, Portland cement, and supplementary cementitious materials (SCM).
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Brimstone selected Dolese Bros following a competitive review of over 23,000 quarries across the country.
In April 2025, primary aluminium imports fell by 20 per cent year-on-year to approximately 281,500 tonnes, down from 352,538 tonnes in April 2024.
The rock for Brimstone’s refinery will come from Dolese’s Roosevelt quarry in southwest Oklahoma, which will also host a USD 378 million demonstration plant. The demonstration plant will be the first realisation of Brimstone’s broader vision: transforming carbon-free calcium silicate rocks into cost-competitive, deeply decarbonised co-products.
Brimstone’s Rock Refinery aims to create the first fully domestic “mine-to-metal” pipeline for aluminium manufacturing in the US.
In 2024, Brimstone was selected for up to USD 189 million in DOE funding to build its Rock Refinery, and it secured around USD 8.7 million for site selection and early development.
Recently, it appealed to the DOE to halt the full award, but continues to move forward with the project while strengthening its partnership with Dolese Bros.
The halt was due to a May 2025 DOE review, which led to the cancellation of 24 clean energy grants totalling USD 3.7 billion — including Brimstone, stating that these awards, “did not meet the economic, national security or energy-security standards” required.
Brimstone co-founder and CEO Cody Finke added, “Following a multi-year, comprehensive review of US quarries to supply the Brimstone Rock Refinery, we’re thrilled to take this step forward in Oklahoma with Dolese Bros. Co.
“Our quarry partner is key to where we site our commercial-scale facility—and, as a trusted industrial supplier with a long, proud tradition in Oklahoma, Dolese Bros. Co. offers exactly what we need to scale: reliable infrastructure, access to markets, developable plant sites, great talent, and of course, the rocks at the core of Brimstone’s process.”
Brimstone aims to begin pilot operations in 2025, with full commercial demonstration targeted by the end of the decade.
In the interim, the company is engaging potential customers and testing its low-carbon cement and SCM offerings.
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