Sr./Staff Mechanical Engineer

The role

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

As a Mechanical Engineer at Mariana Minerals, you will lead the development and deployment of first-of-its-kind chemical refining processes, while also supporting development of software for project execution and plant optimization. You will design, build, and commission mineral processing and metallurgical refining equipment, develop first-principles-based models of refining equipment and processes, and lead equipment scopes from concept through to design, installation, commissioning, ramp, and handover to the operations team.

Posted pay

$140K–$175K

a year

Compared with similar jobs

This base pay is below the median for staff hardware and robotics jobs in the Bay Area.

Median: $203K a year
Other jobs in the group: 134

We compare the middle of each posted range. This is base pay as posted. The group does not include this job.

Location

San Francisco HQ +1

Work type

Onsite

Level

Staff

Posted

Oct 7, 2026

Last check

10 h ago

Job type

Hardware and robotics

The role

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

What you will do

Lead mechanical engineering scopes across project phases—from concept and feasibility through detailed design, procurement, fabrication, installation, and commissioning
Manage vendors throughout the equipment lifecycle—from specification, RFQ, and technical bid evaluation through drawing review and approval, fabrication expediting and inspection (ITP/FAT), delivery, installation and commissioning support, and warranty close-out
Develop site-wide and area-level plant layouts, optimizing equipment arrangement, maintainability access, constructability, safety, and integration with other disciplines
Prepare mechanical equipment specifications, data sheets, and requisition packages for a range of process and solids-handling equipment, and support technical bid evaluations and vendor selection
Perform static equipment design of tanks, silos, bins, pressure vessels, and other stationary equipment, including mechanical sizing, wall/shell thickness, and structural load calculations ensuring code compliance
Conduct finite element analysis (FEA) to validate equipment and component designs for stress, fatigue, thermal, and operational loading conditions
Design, evaluate, and integrate solids-handling and material-conveyance systems, including silos, bins, hoppers, feeders, conveyors, bucket elevators, chutes, and dust-control systems
Support development of 3D models and piping/mechanical interface layouts, ensuring alignment with process, structural, civil, and electrical engineering requirements
Review vendor drawings and calculations, ensuring mechanical design compliance with project requirements, codes, standards, and operability/maintainability expectations
Collaborate with multidisciplinary EPC teams—including process, structural, piping, electrical, instrumentation, and construction management—to deliver cohesive and constructible engineering packages
Provide mechanical engineering support during construction and commissioning, including responding to RFIs, reviewing field changes, and assisting with equipment installation and start-up

Sr./Staff Mechanical Engineer

The role

Sr./Staff Mechanical Engineer

The role

What you will do

What you need

Nice to have

About Mariana Minerals

About Mariana Minerals

Our culture is built on four principles

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Interview questions

Mariana Minerals

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