Process Engineering Intern

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 are hiring a Process Engineering Intern to work on real, high-impact problems within the Pilot Plant Operations team in San Francisco. You will contribute directly to benchtop experiments, pilot plant test runs, and the creation of key plant operational programs, working closely with engineers and domain experts.

This role is designed to provide hands‑on experience building and shipping solutions, not just supporting tasks.

• Drive experiments in the lab and pilot plant to de‑risk scaleup of critical minerals processing steps
• Build, test, and iterate on solutions to increase product recovery, decrease equipment downtime, controls costs, and improve health & safety
• Collaborate with engineering, management, and software engineering to build programs and applications for Mariana’s operations teams
• Collaborate with cross‑functional team members (engineering, operations, analytical lab, etc)
• Present outcomes and learnings at the end of the internship

• Currently pursuing or recently completed degree in chemical engineering, metallurgy, materials science, or a related field
• Strong fundamentals in process design, thermodynamics, and reaction engineering
• Hands‑on experience in a laboratory, pilot plant, or commercial scale plant through previous projects, coursework, and/or internships
• Ability to design experiments, troubleshoot problems, and analyze complex datasets independently
• Excellent technical writing, communication, and teamwork skills
• Comfortable working in fast‑paced environments, wearing multiple hats, and managing ambiguity

At Mariana Minerals, you’ll be part of a mission‑driven team reshaping the way critical minerals are sourced and supplied globally. You’ll have the autonomy to make big decisions, the tools to innovate, and a culture that values ownership, smart automation, and collaboration.

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.

Mariana is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We do not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other protected status.