Sr. Process Engineer

Sr. Process Engineer

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.

Mariana 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.

Work closely with Pilot Plant Technicians to operate, maintain, troubleshoot, and improve pilot-scale processing equipment

Design experiments to evaluate process performance, recovery, throughput, and product quality

Create and maintain key engineering and operational documentation such PFDs, HMBs, P&IDs, Operating Procedures, and Process Control Narratives

Lead equipment design scopes from concept, through procurement, fabrication, installation, commissioning, and handover to Operations

Work 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 scale

Work closely with the software and machine learning teams to develop and implement reactor and plant optimization algorithms

Travel to pilot and commercial sites to drive commissioning, startup, and ramp-up alongside operations & plant design teams

B.S., M.S., or PhD in Chemical Engineering or related field

Minimum 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 industry

Strong understanding of reaction engineering, solid-liquid separation, leaching, ion exchange, solvent extraction, and/or similar unit operations

Hands-on experience designing, commissioning, and operating pilot or commercial-scale process equipment

Ability to design experiments, problem-solve, and analyze complex datasets

Strong commitment to Health & Safety and experience with risk management, management of change, and hazard assessment

Excellent technical writing, communication, and teamwork skills

Comfort working in fast-paced, cross-functional environments

Join us as we build the future of responsible mineral sourcing and supply.