San Francisco-based Mariana Minerals has raised $310 million in Series B funding to expand an unusually ambitious kind of AI business: one that wants to use software and autonomous machinery to produce the copper and lithium needed by data centers, electric vehicles and defense systems. The fresh capital gives the young company a much larger bankroll as it moves from its first operating mine toward a broader domestic critical-minerals portfolio.
The round was led by Menlo Park-based Khosla Ventures, with Andreessen Horowitz and Breakthrough Energy Ventures among the returning investors, according to citybiz. New participants reportedly include Greenoaks, Halo Fund, BHP Ventures, Mitsubishi Corporation, In-Q-Tel and Earthshot Ventures, giving Mariana a mix of venture, industrial and defense-oriented backing.
Mariana Wants To Put An Operating System In A Mine
Mariana is not pitching MarianaOS as software that other mining companies can simply license. The company says it owns and operates its projects, then deploys MarianaOS across mine planning, equipment coordination, refinery management and capital-project execution, as outlined by Mariana Minerals.
Its internal stack combines MineOS, PlantOS and CapitalProjectOS, with machine-learning tools intended to coordinate equipment, respond to changing ore and wastewater conditions, and reduce the stop-start delays that have made large minerals projects notorious for schedule overruns. In less technical terms, Mariana is betting that a mine can use a lot more real-time data and a lot fewer spreadsheets.
CEO and co-founder Turner Caldwell spent nine years at Tesla, including work as a senior manager overseeing battery minerals and metals, before launching Mariana. Caldwell said the new funding will help the company scale what it calls an autonomy-first minerals business, while the company has now raised roughly $400 million in combined parent and project funding, according to citybiz.
Utah Copper And Texas Lithium Are The First Big Tests
Much of the money is earmarked for Copper One in southeastern Utah, where Mariana acquired an existing copper mine and refinery in 2025. The company says mining operations resumed within four months of the acquisition, and its expansion plan targets annual production of 50,000 metric tons of refined copper while adding autonomous haulage, drilling and refinery controls, according to Mariana Minerals.
The second major project is Lithium One in East Texas, which is designed to extract lithium from produced water generated by oil and gas operations rather than relying on a conventional hard-rock mine or evaporation pond. Mariana says the facility is targeting commercial production in the first half of 2027 and could produce up to 3,000 metric tons per year of battery-grade lithium salts, as detailed in the company’s Lithium One announcement.
The Bay Area Startup Is Chasing A National Supply Problem
Mariana’s San Francisco roots place it in familiar Bay Area territory, but its business is built around physical projects scattered across the country. The company has also appeared in a proposed Texas refining effort tied to seafloor-minerals developer TMC, a partnership and feasibility study previously covered by Hoodline’s Brownsville report.
The funding arrives as investors and policymakers increasingly treat copper, lithium and other minerals as strategic infrastructure for the AI economy. Mariana’s pitch is that domestic supply will not be rebuilt quickly enough through traditional mine development alone, so automation has to improve the economics and execution speed of existing and new projects.
That is also where the company faces its biggest test. Software can coordinate trucks, drills, sensors and refinery equipment, but it cannot erase permitting requirements, construction risk, variable geology or the sheer capital intensity of mining; Mariana will have to prove that its technology produces measurable gains in output, cost and commissioning time as Copper One and Lithium One scale.
