Staff Process Engineer
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.
The Role
Mariana Minerals is seeking a highly motivated Process Engineer to support our next-generation minerals processing pilot plant in Houston. You will help design, deploy, and operate first-of-its-kind refining processes for critical minerals. This role is highly hands-on and will play a key role in bridging R&D and plant operations, helping scale technologies from laboratory development through pilot demonstration and ultimately to commercial production. You will work closely with technicians, engineers, and cross-functional teams to ensure processes are robust, safe, and ready for industrial deployment.
What You’ll Do
Lead equipment and process design from concept through procurement, fabrication, installation, commissioning, and startup
Operate, troubleshoot, and improve pilot-scale processing equipment in collaboration with pilot plant technicians
Design and execute pilot-scale experiments to evaluate process performance, recovery, throughput, and product quality
Develop and maintain key process documentation including PFDs, P&IDs, mass and heat balances, operating procedures, and control narratives
Analyze experimental and operational data to identify opportunities for process optimization and scale-up
Support development of automated plant monitoring and optimization tools in collaboration with software and machine learning teams
Ensure safe operations by supporting EHS, hazard assessments, risk management, and management of change processes
What You'll Bring
B.S., M.S., or PhD in Chemical Engineering or a related field
10+ years of experience in operations, process scale-up, or plant design in minerals processing, chemicals, specialty materials, oil & gas, or related industries
Demonstrated experience driving equipment design, commissioning, and plant operation
Strong understanding of relevant unit operations and equipment such as kilns, furnaces, ion exchange, solvent extraction, solid liquid separation, leaching, electrowinning, or similar technologies
Ability to design experiments, troubleshoot complex processes, and analyze operational datasets
Strong commitment to Health, Safety, and Environmental compliance
Excellent technical writing, communication, and teamwork skills
Comfortable working in fast-paced environments, wearing multiple hats, and managing ambiguity
Our culture is built on three principles:
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.
