Staff Process Engineer

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.