Commissioning Engineer

About the role

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. We’re building a core commissioning team of talented, versatile engineers who know how to take a plant from mechanical completion to running. As a Commissioning Engineer, you’ll own electrical and mechanical commissioning scopes: energizing power systems, bringing up equipment and utilities, and getting new systems online safely. You’ll work alongside local commissioning teams, own your commissioning assignments, and make sure we’re building and using our systems throughout commissioning. Your first year will likely be focused on Copper One, our operating copper mine and refinery in Utah, or Lithium One, our new lithium facility in Texas. After that, you’ll go wherever we’re bringing new capacity online, anywhere in the world. Between commissioning pushes, you’ll support design teams and projects at other sites. There’s always something being built. This is a hands-on role for scrappy, collaborative engineers who thrive during startup. You’ll solve problems in the field, do some of your own design work when needed, bring new systems online for the first time, and do it safely, every time. Responsibilities - Lead commissioning teams at various locations. The candidate must be willing to travel to sites during commissioning. - Develop detailed commissioning plans in advance of commissioning activities. - Ensure documentation is complete, including LOTO procedures, work instructions, maintenance procedures, detailed plans, schedules, budgets, etc. - Own scopes relative to engineering expertise. - Lead safe startup practices so everyone gets home safe. - Confirm proper installation and functionality of equipment. Lead specific activities on site during dry and wet commissioning. - Lead ramping activities for assigned commissioning area(s). - Ensure equipment is functional, including controls functionality. - Train and hand over equipment to onsite operators and maintenance personnel. - Serve as a technical expert to assist in process engineering after handover to operations as needed. - Simplify commissioning procedures, then assist in building tools in MarianaOS to automate and scale. - Document and share lessons learned so every site starts from a stronger playbook. - Support design teams and projects at other sites between commissioning cycles. - Contribute to design reviews and HazOps during the design phase. - Travel up to 80%, including extended site assignments during onsite commissioning. Short-notice trips are possible. Between projects, work from a Mariana office or, preferably, an operating asset when needed. Requirements - Bachelor’s degree or higher in chemical, mechanical, electrical, or a related engineering field preferred, or proven hands-on experience commissioning industrial systems. - Hands-on commissioning experience on greenfield or new-plant startups, with deep expertise in electrical or mechanical systems and working knowledge of the other. - Background in battery/EV, semiconductor, data centers, advanced manufacturing, or similar fast-paced industrial environments strongly preferred. - Working knowledge of equipment common in mining and/or refining and plant utilities. - Ability to read and mark up single-lines, P&IDs, schematics, and mechanical drawings. - Desire to help build a smart P&ID system. - Preferred: PLC/controls and instrumentation startup experience, experience at a company that designs, installs, and commissions its own equipment, and comfort using AI tools to speed up your work. - Collaborative by default. You share knowledge openly and make the team around you better. - Strong safety mindset, with experience leading safe energization, LOTO, and startup practices (NFPA 70E). - Valid driver’s license. Safety Safety comes first on every project. You’ll model our site safety policies every day and help lead safe startup practices on site. - Lead JHAs and LOTO for your commissioning scope, follow permit-to-work procedures, and participate in safety meetings, audits, and incident investigations. - Participate in HazOps. - Always wear proper PPE and complete all site safety training. Physical Demands & Work Conditions - Expect heavy on-site work, and extended or irregular hours during commissioning, followed by stretches of remote or office-based work. - Active industrial and construction environments that involve standing, walking, climbing, and working in tight spaces for extended periods, and lifting up to 50 lbs. - Noise, dust, outdoor work in varying weather, and remote site locations. 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!