Lead 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 how minerals are sourced, refined, and optimized by combining deep industrial expertise with software, automation, and data-driven decision-making. Join us as we build the future of responsible mineral sourcing and supply.

Role Overview

Mariana Minerals is looking for a highly motivated Lead Process Engineer to work on building the critical minerals supply chain to support the world’s energy transition.

As the Lead Process Engineer at Mariana Minerals, you will lead the development and deployment of first-of-its-kind chemical refining processes, while also playing a critical role in the development of software for capital project execution and automated plant optimization. Responsibilities will include leading equipment scopes from concept through to design, installation, commissioning, ramp, and handover to the operations team, identifying and evaluating new project opportunities for North American mineral refining, and supporting the buildout and leading an in-house process engineering team.

What You’ll Do

• Lead 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

• Drive cross-functional teams of lab technicians, pilot plant engineers, process engineers, and project engineers to lead the technical equipment scale-up and de-risk the commercialization of novel mineral refining processes

• Support the hiring, mentorship, and day-to-day management of junior process engineers

• Develop technoeconomic models of new project opportunities, acquisition targets, and new technologies to inform business development

• Prepare and present bankable engineering deliverables to support project financing partners due diligence reviews

• Identify, evaluate, and implement engineering solutions to optimize extraction, purification, and recovery processes under varying chemistry, feedstock qualities, and operating conditions

• Collaborate deeply with R&D, lab staff, pilot-plant engineers, and operations teams to translate bench-scale insights into robust and scalable flowsheets

• Identify, evaluate, and implement process engineering and project management software tools

• Identify and support opportunities for the software and machine learning teams to automate capital project execution workflows and develop advanced plant control algorithms

What You’ll Bring

• 10+ years of engineering experience in industrial, chemical, mineral processing, or similar process-intensive environments

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

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

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

• Brownfield modifications and upgrades of process equipment (e.g., leach tanks, reactors, filtration systems, solvent extraction circuits)

• Greenfield design of hydrometallurgical unit operations and integrated circuits

• Troubleshooting, evaluation, and optimization of operating hydrometallurgical or chemical-process equipment

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

• Hydrometallurgical mineral processing or metal refining

• Lithium processing and refining

• Large-scale mining, critical-minerals processing, or battery-materials production

• Industrial chemical manufacturing with complex aqueous/chemical reaction systems

• Engineering, procurement, and construction (EPC/EPCM) firms supporting mining and mineral processing industry projects

• Experience with direct or indirect leadership of engineers and technicians

Why This Role

Mining is one of the most operationally complex industries on earth—and one of the least digitized. Most mines run on disconnected systems, tribal knowledge, and decisions made by feel rather than data.

At Mariana, you'll build the software that changes this. You'll work on autonomous haul trucks, integrated mine planning, and optimization systems that treat the entire mine as a single coordinated operation. If you want to work on hard problems with real-world stakes, this is it.

What It's Like to Work Here

Extreme Ownership – We take full responsibility for outcomes and drive relentlessly toward solutions.

Engineer Out, Then Automate – We simplify and optimize before we scale.

Share Your Legos – We collaborate openly, share knowledge freely, and help each other build better solutions.

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.