California-based Brimstone, in partnership with Oklahoma City–based Dolese Bros., will invest approximately $400 million to construct a demonstration alumina refinery near Lawton or Duncan, Oklahoma. The 20-acre facility is designed to produce 80 000 t/year of “green” Portland cement and 20 000 t/year of smelter-grade alumina using Brimstone’s patented Rock Refinery™ process to extract alumina directly from locally abundant, alumina- and calcium-rich silicate rocks at the Roosevelt quarry—replacing traditional imported bauxite and the high-carbon-intensity Bayer process. The project is slated to reach full production before 2030 and is expected to create several hundred local jobs during both construction and operation. Brimstone is currently appealing the U.S. Department of Energy’s suspension of a $189 million clean-energy demonstration grant awarded in 2024 and is working with congressional representatives to restore the funding. The company emphasizes that, while the federal grant serves as a catalyst for accelerating the project, the demonstration plant will proceed in Oklahoma regardless of federal support.