The United States' precarious dependence on Chinese-processed critical minerals has drawn a $310 million bet from prominent Silicon Valley venture capital firms, as the artificial intelligence boom intensifies demand for copper, lithium, and rare earth elements. Mariana Minerals, a San Francisco-based startup deploying autonomous software to restart idled American mines, announced the Series B round led by Khosla Ventures, bringing its total funding to $400 million.
American Minerals for American Industry
The funding directly supports domestic extraction at a moment when China controls an estimated 90% of global critical minerals processing. For rare earth magnets essential to defense applications and consumer electronics, that figure reaches 92%. Decades of Chinese industrial policy and domestic deindustrialization have left American manufacturing vulnerable to supply chain disruption and price manipulation.
"We're entering a metals-driven economy," said Turner Caldwell, Mariana's CEO and a former Tesla factory design executive. "Our goal is to reduce the cost of these core inputs to the modern economy over time. That enables us to ensure that everything downstream can move as fast as humanly possible."
The company has already acquired and restarted the Copper One mine in Utah, which it claims is moving toward producing 50,000 metric tons of refined copper annually. Lithium One in Texas broke ground in 2025 with commercial production expected by 2027. Both operations rely on Mariana's proprietary software backbone designed to generalize across aluminum, magnesium, nickel, cobalt, manganese, uranium, and rare earths.
"You cannot lead in the AI century without a domestic critical minerals supply chain. The AI revolution, physically speaking, depends on the mining of a huge amount of minerals and metals."
National Security Implications
Andreessen Horowitz and Breakthrough Energy Ventures joined the round alongside BHP Ventures, Mitsubishi Corporation, and Washington Harbour Partners. The broad coalition reflects growing recognition that AI infrastructure, electric grid expansion, and defense systems all originate at the minehead.
While the Biden and Trump administrations have both acknowledged the critical minerals crisis through executive orders and Defense Production Act authorities, domestic mining investment has lagged behind policy rhetoric. Mariana's $1.5 billion valuation signals that private capital now treats mineral sovereignty as an urgent economic and national security imperative rather than a niche concern.