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The San Francisco, California-based company’s first project is extracting lithium from oilfield brines in western Louisiana and east Texas, Turner Caldwell said in an interview on Thursday February 19.
Caldwell described the plant as a test of a software-first approach to mining.
Brine from about 1,000 oil wells is diverted to Mariana’s plant, where lithium is extracted and the water returned to its owner. The resource’s lithium concentrations — around 100 milligrams per liter — are higher than other US formations, making it ideal for the new technology.
The first commercial unit, known as Lithium One, is designed as a gigawatt-hour-scale facility capable of producing up to 3,000 tonnes per year of battery-grade lithium salts. The company expects it to enter commercial production in the first half of 2027.
“We’ve built the project to stay cash flow positive even in the lower price environment we’ve seen over the last few years. Customer pricing, of course, needs to reflect the investment required and deliver the returns our shareholders expect,” Caldwell said.
“When we layer in the reinforcement learning side of things, we’re seeing a path toward a 20% reduction — from labor, preventive maintenance, recovery, reagent consumption and energy use,” he added.
Reinforcement learning (RL) is a type of software that continuously adjusts plant operations to maximize lithium recovery and minimize waste. Traditionally, engineers would sample brine, analyze results and make adjustments periodically. With RL, the system monitors conditions in real time and tweaks flows, temperatures and other variables across the processing circuit.
“The plant is effectively making the decisions engineers normally make, but faster and with more precision,” Caldwell said. “It’s particularly valuable because feedstock can vary — different wells produce slightly different brines — and the software can react immediately instead of waiting hours for human analysis,” he added.
Caldwell stressed that the value comes from controlling the whole circuit, not just the lithium extraction step. “Direct lithium extraction is one part of the process. The software sees the entire circuit and optimizes recovery, energy use, and chemical use as a single problem, rather than optimizing each step separately,” he told Fastmarkets.
Mariana is deliberately avoiding the traditional model of building a single, massive plant. Instead, it standardizes ‘line’ sizes that can be replicated across multiple sites, Caldwell said, to allow faster deployment, more predictable ramp-ups and reduced delivery risks.
“You sign yourself up for multi-year project cycles when you chase massive scale,” Caldwell noted. “We’re keeping first plants smaller, then replicating. Standardization is key,” he added.
Site infrastructure — power, water and other utilities — is also a major factor. Caldwell noted that Mariana is a developer-operator: it builds and runs its plants, rather than licensing the technology or acting as a software vendor.
In the near term, Mariana will produce lithium carbonate, which is widely accepted across battery chemistries.
Caldwell said this gives the company flexibility to sell to multiple buyers or feed downstream production.
Long-term offtake agreements are being negotiated with OEMs and intermediaries, with some flexibility retained through trading partners, he added.
“Focus on the short term has got to be on lithium carbonate,” he said. “It gives you fungibility to either sell it or feed production circuits. Long-term, this will allow us to respond to market shifts without being locked into a single pathway,” he added.
Caldwell emphasized that the same software-driven approach isn’t limited to lithium.
“Our platform is designed to work across other critical minerals, including copper, nickel, and cobalt,” he said. “The principles are the same: optimize the full processing circuit, reduce costs and respond in real time to variable feedstocks. Lithium is just the first test case.”
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