Mariana Minerals secures $310 million Series B to boost U.S. metal mining

Mariana Minerals, a software-driven mining startup founded by Turner Caldwell, Baker Tilney and Juan Lozano, closed a $310 million Series B financing round headed by Khosla Ventures, with Andreessen Horowitz and a slate of other investors also contributing. The new money brings the company’s cumulative funding to $400 million and assigns it a $1.5 billion valuation. Mariana will deploy the proceeds to its two operating assets - Copper One, a revived copper mine in Utah, and Lithium One, a Texas project slated for commercial output in 2027 - while expanding its autonomous mining software across additional metals.

Caldwell emphasizes that reducing the cost of metals such as copper, lithium, aluminum and rare earths is essential for the United States to sustain AI, electrification and other high-growth sectors. Industry observers, including former Uber founder Travis Kalanick, note that a domestic supply chain for these minerals is critical to national competitiveness. The financing positions Mariana to challenge established miners like Standard Lithium and BHP Group as demand for critical minerals accelerates.