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 Staff Process Modeling Engineer to support the development of next-generation refining processes for critical minerals — key to enabling the world’s energy transition.

In this role, you will be responsible for developing, validating, and optimizing heat and material balance models using tools such as ASPEN Plus/HYSYS, SysCAD, OLI Studio, or METSIM. You will work closely with R&D, pilot operations, and project execution teams to translate lab and pilot data into robust, scalable process models that drive the design of first-of-a-kind mineral refining facilities.

As a Staff Process Modeling Engineer, you will serve as a technical leader for process simulation and modeling, providing subject matter expertise across multiple projects, developing modeling standards and best practices, and mentoring junior engineers while partnering with cross-functional teams to support process development from concept through commercial deployment.

What You’ll Do

• Develop steady-state and dynamic process models to establish heat and material balances for integrated mineral refinery systems using ASPEN, SysCAD, OLI, or METSIM.

• Automate equipment and process sizing (reactors, heat exchangers, filters, crystallizers, evaporators, and separators) based on model outputs, linking models to datasheets and other engineering tools

• Develop and maintain process simulation databases, ensuring consistency and traceability between modeling assumptions, test data, and engineering deliverables.

• Calibrate and reconcile models using pilot or plant operating data to ensure model fidelity and predictive accuracy.

• Conduct process optimization studies — evaluating energy/heat recovery, recycle strategies, and material efficiency improvements.

• Develop dynamic process models to validate PLC and DCS programming and evaluate/optimize buffer sizing throughout the design.

• Link process models to CAPEX and OPEX estimation tools, automating technoeconomic model development

• Document modeling methodologies and results, providing clear technical communication for design reviews, techno-economic assessments, and regulatory submissions.

What You’ll Bring

• Bachelor's degree or higher in Chemical Engineering, Mechanical Engineering, Process Engineering, Metallurgical Engineering, or a closely related engineering discipline

• 8+ years of experience developing and applying process simulation models for chemical processing, hydrometallurgy, mining, refining, or related industrial process systems.

• Proficiency in one or more of the following process simulation tools:

  • ASPEN Plus / HYSYS

  • SysCAD

  • OLI Studio / OLI Flowsheet

  • METSIM

• Deep understanding of mass transfer, heat transfer, thermodynamics, fluid flow, and reaction engineering.

• Experience developing material and energy balances for multi-step, integrated process systems.

• Strong grasp of chemical equilibria and phase behavior in aqueous and non-aqueous systems.

• Familiarity with data reconciliation, parameter fitting, and model validation using experimental or operational data.

• Competency with Python or MATLAB for model automation, data processing, and custom calculations is a strong plus.

• Experience integrating process modeling outputs into EPC deliverables (PFDs, P&IDs, equipment datasheets, control narratives, etc.)

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.