Mariana Minerals Announces Series B Funding

Mariana Minerals, a software-first, vertically integrated minerals company focused on supplying the minerals critical to modern energy, AI, and defense technologies, led by Turner Caldwell and the team, has announced its $310 million Series B financing, led by Khosla Ventures, with continued support from Andreessen Horowitz (a16z) and Breakthrough Energy Ventures, and new participation from Greenoaks, Halo Fund, Pax Ventures, StepStone Group, BHP Ventures, Washington Harbour Partners, Greycroft, General Innovation Capital Partners, Mitsubishi Corporation, In-Q-Tel (IQT), and Earthshot Ventures, with a number of additional strategic capital partners joining the round. This round brings the company’s total parent and project capital raised to date to approximately $400 million. 

Demand for critical minerals is accelerating across major industries, from AI infrastructure and electrification to grid expansion and aerospace. Meeting this demand will require new mining and refining capacity alongside greater metal recycling. Yet the cost and time required to expand mineral infrastructure continue to rise as ore grades decline, deposits become deeper, and mineralogies grow more complex. Slow technology adoption has further limited the industry’s ability to overcome these challenges.

Mariana Minerals is addressing this gap through a vertically integrated model focused on end-to-end autonomy, faster deployment, and lower costs. At the core is MarianaOS, a software stack built around three operating systems designed to enable better mining, processing, and refining.

CapitalProjectOS – Build Better:

CapitalProjectOS is an integrated project lifecycle management platform that breaks down data silos and uses AI agents to automate manual workflows. With more than 90% of mega projects experiencing budget or schedule overruns, the platform consolidates engineering deliverables, equipment data, procurement, scheduling, and cost controls into a unified, data-driven environment, cutting deployment time and costs by up to half.

By automating data pipelines and bringing project context into a single data layer, CapitalProjectOS delivers the right information to the right people at the right time, enabling AI agents to support engineering, procurement, and construction management. The result is a more efficient and capable project team.

MineOS – Mine Better:

A modern mine requires thousands of interdependent decisions every day across geology, drill-and-blast, fleet operations, and processing. Today, these decisions are often siloed and reconciled through manual coordination, creating shift-to-shift variability and exposing a growing talent gap as experienced operators retire.

MineOS combines physics-informed world models with reinforcement learning agents to orchestrate mining fleets in a closed loop. By connecting block models, mine plans, equipment, and telemetry through a unified operating system, MineOS enables data-driven decisions across the operation with less manual intervention.

PlantOS – Refine Better:

Mineral processing plants and refineries often adjust operating conditions only a few times a week, relying on manual sampling and human review. PlantOS replaces this slow feedback loop with inline sensing and reinforcement learning (RL) control.

Lab experiments and kinetic modeling create a digital “world model” of the refinery, where RL agents learn optimal operating strategies through simulation before connecting to the real plant’s control system. Once deployed, the system continuously uses sensor feedback and control signals to optimize operations.

The same RL architecture is being applied across seven unit operations at Copper One and Lithium One, spanning brine pretreatment, direct lithium extraction, osmotically assisted reverse osmosis, heap (bio)leaching, solvent extraction, electrowinning, and oxidative leaching.

CapitalProjectOS, MineOS, and PlantOS form the core pillars of MarianaOS, a unified platform connecting the pit to the plant. The systems are already deployed across the Copper One and Lithium One sites.

At Copper One, Mariana compressed the traditional multi-year acquisition, permitting, and restart process into months. At Lithium One, the company is on track to bring its first purpose-built, autonomous greenfield refinery online in less than three years of founding Mariana.

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