Senior Process Engineer

Sr. Process EngineerMariana 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.Role OverviewMariana Minerals is looking for a highly motivated Sr. Process Engineer to join our San Francisco Pilot Plant team. You will lead the design, deployment, and operation of first-of-its-kind refining processes for critical minerals, while also supporting development of software for automated plant optimization. This position is highly hands-on and will play a critical role in bridging R&D and Operations, ensuring processes are robust, safe, cost-effective, and suitable for commercial production.What You'll DoWork closely with Pilot Plant Technicians to operate, maintain, troubleshoot, and improve pilot-scale processing equipmentDesign experiments to evaluate process performance, recovery, throughput, and product qualityCreate and maintain key engineering and operational documentation such PFDs, HMBs, P&IDs, Operating Procedures, and Process Control NarrativesLead equipment design scopes from concept, through procurement, fabrication, installation, commissioning, and handover to OperationsWork closely with cross-functional teams including R&D, commercial plant design engineers, project execution teams, and more to scale designs from lab to the pilot to production scaleWork closely with the software and machine learning teams to develop and implement reactor and plant optimization algorithmsTravel to pilot and commercial sites to drive commissioning, startup, and ramp-up alongside operations & plant design teamsWhat You'll BringB.S., M.S., or PhD in Chemical Engineering or related fieldMinimum of 5 years of experience supporting R&D scale up, pilot plant operation, and/or commercial production in minerals processing, chemicals, specialty materials, oil & gas, or similar industryStrong understanding of reaction engineering, solid-liquid separation, leaching, ion exchange, solvent extraction, and/or similar unit operationsHands-on experience designing, commissioning, and operating pilot or commercial-scale process equipmentAbility to design experiments, problem-solve, and analyze complex datasetsStrong commitment to Health & Safety and experience with risk management, management of change, and hazard assessmentExcellent technical writing, communication, and teamwork skillsComfort working in fast-paced, cross-functional environmentsOur Culture Is Built On Four PrinciplesEveryone 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!