--- title: 'Process Engineer at Mariana Minerals' canonical: 'https://feeny.ai/job/process-engineer-mariana-minerals-moab-5tajjyjgxp0g' type: 'job' last_seen: '2026-10-30' --- # Process Engineer at Mariana Minerals - **Company:** Mariana Minerals - **Location:** Moab, UT - **Employment:** full-time - **Work type:** onsite - **Posted:** 2026-10-26 - **Last confirmed live:** 2026-10-30 - **Apply:** https://jobs.ashbyhq.com/marianaminerals/774bafd4-62ee-4fd8-a3f0-2e43019788ec ## Job description ## About Mariana Minerals Mariana Minerals is a software-first, vertically integrated minerals company on a mission to supply the critical minerals powering modern energy, AI, and defense technologies. We’re reimagining the minerals supply chain by combining deep industry expertise with advanced software, automation, and data-driven decision-making. ## Key responsibilities Process ownership – SX and EW - Act as the engineering owner of the SX and EW circuits, including mixer-settlers, organic and electrolyte handling, tank house, cell house and associated utilities. - Monitor daily plant performance (PLS grade and flow, extraction and stripping efficiency, phase continuity, entrainment, current efficiency, cathode quality) and act on deviations. - Define and maintain operating envelopes, control set points and alarm limits together with operations and control engineers. - Lead technical troubleshooting of process upsets such as crud formation, organic degradation, impurity build-up (Fe, Mn, Cl, NO₃), short circuits and poor cathode morphology. - Manage reagent strategy for extractant, diluent, smoothing agents and cobalt sulfate, including consumption tracking and supplier technical liaison. - Produce daily, weekly and monthly process performance reports and metallurgical balances. Process improvement - Identify, evaluate and lead improvement projects that increase recovery, throughput, current efficiency and cathode grade, or reduce energy, reagent and operating costs. - Use data analysis, mass and energy balances, and process modeling to quantify opportunities and build business cases. - Plan and run plant trials and test work with the laboratory, vendors and external partners, then implement and verify results. - Drive root-cause analysis on recurring losses and production incidents, and track corrective actions to closure. - Support control-system optimization and the use of instrumentation and online analyzers. Expansion and capital projects - Provide process input to studies for capacity expansion, debottlenecking and new circuits, from concept through feasibility and detailed design. - Develop and review process design criteria, PFDs, P&IDs, mass balances, equipment sizing and datasheets. - Represent operations in design reviews, HAZOP and constructability workshops so new assets are operable and maintainable. - Support pre-commissioning, commissioning and ramp-up of new or modified equipment. - Contribute to cost estimates, schedules and risk assessments for capital projects. Safety, standards and people - Apply process safety and management-of-change (MOC) practice to every process modification, with particular focus on fire risk in SX and acid mist in EW. - Write and update SOPs, process descriptions and training material for operators. - Coach operators, metallurgists and junior engineers, and share knowledge across teams. - Support environmental compliance for effluents, emissions and organic losses. Required qualifications - This role suits a hands-on hydrometallurgical/mechanical/chemical engineer who enjoys spending time in the plant, turning data into decisions, and seeing improvements through from idea to commissioning. - 2+ years of process engineering experience in commissioning of chemical factories, mechanical equipment knowledge or project/design upgrades. - Proven track record delivering process improvement projects with measurable results. Our culture is built on four principles: Everyone Gets Home Safe. We never put speed or cost ahead of people. Extreme Ownership. We take full responsibility for outcomes, relentlessly driving toward solutions. Engineer Out Requirements, then Automate. We simplify, optimize, and then automate for scale. Share Your Legos. We collaborate openly, share knowledge, and empower each other to build bigger, better solutions. Join us as we build the future of responsible mineral sourcing and supply! ## About Mariana Minerals ## Company Overview - **One-liner**: Mariana Minerals is a software-first, vertically integrated minerals company focused on supplying the minerals critical to modern energy, AI, and defense technologies. - **Entity Type**: Private (Series A, $85M funding in July 2025) - **Headquarters**: San Francisco, California, United States - **Founded**: Not publicly available - **Founders**: Turner Caldwell (Co-Founder & CEO) ## Core Business - **Primary industry**: Metal Ore Mining / Critical Minerals - **Target customers**: B2B – energy, AI, and defense supply chains (including downstream manufacturers and government entities) - **Mission or purpose**: "Create a future of critical mineral abundance" by reimagining the global minerals supply chain with software, automation, and data-driven decision making. ## Products & Services - **Copper One (formerly Lisbon Valley Copper Mine)**: World’s first autonomous mine, located in Utah. Produces copper using integrated automation and software control. Restarted production in April 2026. - **Lithium One**: Lithium project (on the roadmap or early development). - **Other mineral projects**: Graphite, Uranium, Rare Earth Metals, Cobalt, Nickel, Aluminium – at various stages (stealth or roadmap). - **CapitalProjectOS**: Internal software platform for capital project management (mentioned in leadership bio). - **Technology Stack**: React, dbt, TypeScript, Python, TensorFlow, PyTorch, microservices, SCADA, Autodesk, and many others – indicating a strong software engineering backbone. ## Market Standing - **Valuation/Market Cap**: Not disclosed (private company) - **Key Metric**: Total funding – $85M Series A (July 2025, 1 investor) - **Notable Investors/Partners**: Lead investor not publicly disclosed (Andreessen Horowitz was pitched but not confirmed as an investor). Partners include Bot Auto, WeRide, Pronto, Atoms (based on LinkedIn mentions). Also works with UMA (Utah Mining Association). - **Growth Signals**: Headcount grew 3,575% YoY to 107 employees (as of mid-2026). 73 active job postings. Opened the world’s first autonomous mine (Copper One) in April/May 2026, generating significant industry news and social media engagement. ## Competitive Advantages - **Software-first approach**: The company builds automation and data systems from the ground up, rather than layering tech onto legacy mining operations. This enables fully autonomous mining. - **Vertical integration**: They develop, own, and operate mineral projects, controlling the entire value chain from extraction to processing. - **Deep tech stack**: Use of AI/ML (TensorFlow, PyTorch), simulation, and real-time control systems to optimize mining operations. - **First-mover in autonomous mining**: Copper One is claimed to be the world’s first autonomous mine, giving them a significant lead in operational efficiency and safety. ## Strategic Focus - Scale autonomous mining operations beyond copper (lithium, graphite, uranium, etc.) - Secure domestic supply of critical minerals for U.S. energy, AI, and defense needs. - Continue aggressive hiring across engineering, operations, and field roles. - Expand from Utah to additional sites (Houston engineering office, potential new projects). ## Why Work Here - **Culture principles**: "Extreme Ownership", "Engineer Out Requirements, Then Automate", "Share Your Legos" – emphasizing accountability, simplification, and collaboration. - **Work environment**: High-growth startup with a mission-driven focus on critical infrastructure. Offices in San Francisco (HQ), Houston (Engineering), and La Sal, Utah (mine site). Hybrid/remote policy not explicitly stated, but multiple office locations suggest flexibility for field vs. office roles. - **Notable perks**: Opportunity to work on cutting-edge autonomous systems and AI in a traditional industry. Strong engineering culture with modern tech stack (React, Python, ML). Rapid career growth due to company expansion. - **Talent sources**: Attracts talent from Tesla, Redwood Materials, Lilac, ExxonMobil, Amazon Web Services, and other tech/energy companies – indicating a high-caliber peer group. ## Sources 1. [marianaminerals.com](https://marianaminerals.com/) 2. [marianaminerals.com/careers](https://marianaminerals.com/careers) 3. [marianaminerals.com/about](https://marianaminerals.com/about) 4. [jobs.ashbyhq.com/marianaminerals](https://jobs.ashbyhq.com/marianaminerals) 5. [linkedin.com/company/mariana-minerals](https://www.linkedin.com/company/mariana-minerals) ## Other roles at Mariana Minerals - [Stacking/Sizer Operator](https://feeny.ai/job/stacking-sizer-operator-mariana-minerals-moab-q08nvmvtbbap) — Moab, UT - [R&D Technician](https://feeny.ai/job/r-d-technician-mariana-minerals-san-francisco-3q98f6mnvpmg) — San Francisco, CA - [Analytical Lab Chemist](https://feeny.ai/job/analytical-lab-chemist-mariana-minerals-san-francisco-dwx9kyd8dfqn) — San Francisco, CA - [Mobile Maintenance Supervisor](https://feeny.ai/job/mobile-maintenance-supervisor-mariana-minerals-moab-7ewztvzzvw62) — Moab, UT - [Administrative Assistant](https://feeny.ai/job/administrative-assistant-mariana-minerals-houston-bamf8ahyve5k) — Houston, TX - [Senior/Staff Chemical Process Engineer](https://feeny.ai/job/senior-staff-chemical-process-engineer-mariana-minerals-san-francisco-34b0xfs3fzep) — San Francisco, CA - [Controls Technician](https://feeny.ai/job/controls-technician-mariana-minerals-joaquin-rj03sx442xtf) — Joaquin, TX - [Associate, Corporate Development](https://feeny.ai/job/associate-corporate-development-mariana-minerals-houston-rbz4jm1qw29v) — Houston, TX - [Manager, Corporate Development](https://feeny.ai/job/manager-corporate-development-mariana-minerals-houston-zeyejbwkyfbj) — Houston, TX - [Process Maintenance Technician](https://feeny.ai/job/process-maintenance-technician-mariana-minerals-moab-krhtmk9tqnmf) — Moab, UT