Senior Plant Manager

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 Plant Manager to lead the development and operation of our next-generation minerals processing pilot facility in Houston. You will be responsible for establishing and operating a first-of-its-kind pilot plant, including site setup, equipment design, construction, commissioning, start-up, and ongoing operations. You will help build and lead a multidisciplinary team of engineers and technicians to develop, test, and optimize innovative refining processes for critical minerals. This role serves as a critical bridge between R&D and commercial deployment, ensuring technologies are safely and effectively scaled from pilot to industrial production. What You’ll Do Lead the design, construction, commissioning, and startup of Mariana’s Houston pilot plant facility. Oversee day-to-day pilot plant operations to ensure safe, reliable, and efficient execution of minerals refining processes. Oversee the design and execution of pilot-scale experiments to validate reaction parameters, optimize yields, and demonstrate process reproducibility. Drive the creation and upkeep of process documentation including PFDs, P&IDs, mass/energy balances, and operating procedures. Recruit, build, and manage a team of engineers and technicians to support pilot plant development and operations. Collaborate with R&D, engineering, and commercial design teams to scale processes from lab development to commercial production. Own and manage the site budget, including capital expenditures, operating costs, and contractor/vendor management Establish and enforce Environmental, Health & Safety (EHS) and Process Safety Management (PSM) programs and operational standards. Desired Qualifications B.S., M.S., or PhD in 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 leading equipment design, construction, commissioning, and startup Strong understanding of relevant unit operations and equipment such as kilns, furnaces, ion exchange, solvent extraction, solid liquid separation, leaching, electrowinning, or similar technologies Experience translating R&D processes into pilot and commercial-scale operations Proven experience implementing EHS and Process Safety Management programs Strong leadership and project management skills with experience managing technical teams and complex projects Comfortable working in fast-paced environments, wearing multiple hats, and managing ambiguity Why Join Us? 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. 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. 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.

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