Staff Mechanical Engineer

Department: Process Development

Location: Houston, TX

Compensation: $140K – $175K • Offers Equity

Employment Type: FullTime

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 Mechanical Engineer to support our next-generation minerals processing pilot plant in Houston. You will lead the design, integration, and deployment of pilot-scale mechanical systems and processing equipment used to demonstrate and scale innovative refining technologies for critical minerals. This role is highly hands-on and will play a key role in building and maintaining a first-of-its-kind pilot plant. You will work closely with process engineers, technicians, and cross-functional teams to design, install, commission, and improve pilot-scale equipment while ensuring systems are reliable, safe, and scalable to commercial production.

What You’ll Do

• Design, specify, and deploy mechanical systems and equipment for pilot-scale mineral processing operations

• Work closely with process engineers to translate process requirements into practical mechanical and plant designs

• Support installation, troubleshooting, and maintenance of pilot plant equipment including pumps, piping systems, reactors, separators, filtration systems, and material handling equipment

• Develop and maintain mechanical design documentation including equipment specifications, layout drawings, piping schematics, and CAD models

• Identify opportunities to improve equipment reliability, maintainability, and operational performance

• Coordinate with vendors, fabricators, and contractors during equipment procurement and installation

• Support safe plant operations by contributing to hazard reviews, equipment safety design, and mechanical integrity programs

Desired Qualifications

• B.S., M.S., or PhD in Mechanical Engineering or a related field

• 9+ years of experience in 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

• Experience designing and maintaining furnaces, pumps and fluid handling systems, pressure vessels and reactors, piping systems and valves, filtration and separation equipment, and materials handling systems

• Ability to work closely with cross-functional teams including process engineering, operations, 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, wearing multiple hats, and managing ambiguity

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.