Senior/Staff Chemical 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. Role Overview Mariana Minerals is looking for a highly motivated Sr./Staff Process Engineer to work on building the critical minerals supply chain to support the world’s energy transition and to supply metals necessary for technology and AI, energy, mobility, and defense. As a Sr./Staff Process Engineer at Mariana Minerals, you will lead the development and deployment of state-of-the-art chemical refining processes, while also supporting development of software for capital project execution and automated plant optimization. Responsibilities will include leading process area and equipment scopes from concept through to design, installation, commissioning, ramp, and handover to the operations team. What You’ll Bring

• Lead process area and equipment scopes from concept and modeling validation, through procurement, engineering, fabrication, installation, commissioning, and ramp

• Manage external equipment providers, technology licensors, and engineering companies to deliver fully integrated and functional mineral refining scopes.

• Build heat and material balances for integrated mineral refineries

• Develop Process Flow Diagrams (PFDs) and Piping & Instrumentation Diagrams (P&IDs) for mineral refineries

• Build first-principles-based models of chemical reactors and unit operations to validate and scale-up designs

• Identify, evaluate, and implement engineering solutions to optimize process designs, confirming functionality and performance under various operating conditions

• Work closely with cross-functional teams including lab technicians, pilot plant engineers, process engineers, project execution teams, and more to scale designs from lab through to commercial scale

• Work closely with the software and machine learning teams to automate capital project execution workflows and develop equipment and plant optimization algorithms

What You’ll Bring

• Strong understanding of engineering fundamentals and demonstrated ability to leverage this understanding to solve challenging problems

• Strong foundation in chemical engineering, metallurgical engineering, or process engineering, with demonstrated ability to apply engineering fundamentals to complex systems

• Experience with plant & equipment engineering and design. Including but not limited to:

• Brownfield modifications and upgrades

• Greenfield design

• Evaluation and optimization of operating facilities

• Experience with the following industries and/or production environments:

• Industrial manufacturing

• Large-scale mining or mineral processing, particularly across hydrometallurgy, electrometallurgy, and pyrometallurgy

• Large-scale chemical production processes

• Engineering, procurement, and construction (EPC/EPCM) firms

Our culture is built on four principles:

Everyone Gets Home Safe. We never put speed or cost ahead of people. 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!