Mechanical Engineer

Marianaminerals

San Francisco HQ

On-site

Who this role is best for

Aimed at mid-level to senior Mechanical Engineers who can bridge R&D and operations with hands-on experience in plant design and commissioning.

Best fit for

Candidates with experience in minerals processing or related industries and a background in plant design and commissioning
— “Experience in automated manufacturing, operations, process scale-up, or plant design in minerals processing”
Individuals who are comfortable taking on multiple roles across engineering, operations, and project execution
— “Ability to wear multiple hats and take on additional scope in areas such as process engineering, operations, maintenance, and project execution”
Candidates with a proven track record in equipment design, commissioning, and mechanical reliability
— “Demonstrated experience driving equipment design, commissioning, operations, and reliability”

Things to consider

Travel is a significant component of the role, requiring on-site presence at Mariana sites
— “Travel to Mariana sites to support new projects, start-up/commissioning, and troubleshooting initiatives”
The role demands a strong emphasis on health, safety, and environmental standards
— “Strong commitment to Health, Safety and Environmental compliance and mechanical integrity standards”

How to stand out

Highlight experience in translating process requirements into mechanical designs and plant improvements
— “Work closely with process engineers and R&D scientists to translate process requirements into equipment modifications”
Emphasize your ability to troubleshoot mechanical issues in hands-on plant environments
— “Troubleshoot mechanical issues and implement practical solutions to maintain safe, reliable, and efficient plant operations”
Showcase your technical writing skills with examples of engineering documentation you have created
— “Create and maintain engineering documentation, including P&IDs, process and control narratives”
Demonstrate your comfort with fast-paced environments and managing ambiguity
— “Comfortable working in fast-paced environments and managing ambiguity”
Position yourself as a collaborator who can share knowledge and support team-driven solutions
— “Share Your Legos. We collaborate openly, share knowledge, and empower each other to build bigger, better solutions.”

Pace · SteadyCollaboration · HighAutonomy · MediumDecision Impact · Team

Derived from job-description analysis by Serendipath's career intelligence engine.

What success looks like

drive equipment design and commissioning
improve equipment reliability

Typical background

B.S., M.S., or PhD in Mechanical Engineering

Skills & requirements

Required

Mechanical EngineeringPlant DesignTroubleshootingProcess EngineeringOperationsMaintenance

Preferred

Software DevelopmentProject Execution

Stack & domain

Mechanical EngineeringProcess EngineeringPlant DesignCAD ModelsSoftware DevelopmentTroubleshootingProblem-solvingTeamworkCommunicationCommitment To SafetyMiningManufacturingAutomation

About the role

Original posting from Marianaminerals via Ashby

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 looking for a highly motivated Mechanical Engineer to join our San Francisco Pilot Plant team. You will support the design, installation, and maintenance of first-of-its-kind refining processes for critical minerals. This position plays a critical role in bridging R&D and Operations, ensuring our equipment and work processes are robust, safe, cost-effective, and suitable for commercial production.
WHAT YOU'LL DO
Drive design, fabrication, installation, modification, startup, and commissioning of new equipment and pilot plant systems.
Troubleshoot mechanical issues and implement practical solutions to maintain safe, reliable, and efficient plant operations.
Work closely with process engineers and R&D scientists to translate process requirements into equipment modifications, mechanical designs, and plant improvements.
Create and maintain engineering documentation, including P&IDs, process and control narratives, equipment specifications, drawings, CAD models, and equipment manuals.
Identify opportunities to improve equipment reliability, maintainability, and operational performance
Support the development of software and to help drive rapid equipment design, plant reliability, and safe operation
Travel to Mariana sites to support new projects, start-up/commissioning, and troubleshooting initiatives
WHAT YOU'LL BRING
B.S., M.S., or PhD in Mechanical Engineering or a related field
Experience in automated manufacturing, operations, process scale-up, or plant design in minerals processing, chemicals, specialty materials, oil & gas, or related industries
Demonstrated experience driving equipment design, commissioning, operations, and reliability
Ability to wear multiple hats and take on additional scope in areas such as process engineering, operations, maintenance, and project execution
Strong troubleshooting and problem-solving skills in hands-on plant environments
Strong commitment to Health, Safety, and Environmental compliance and mechanical integrity standards
Excellent technical writing, communication, and teamwork skills
Comfortable working in fast-paced environments and managing ambiguity
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!

Source: Marianaminerals careers (Ashby)