---
title: 'Mechanical Engineer at Mariana Minerals'
canonical: 'https://feeny.ai/job/mechanical-engineer-mariana-minerals-san-francisco-dv7an46y7ypw'
type: 'job'
last_seen: '2026-09-11'
---

# Mechanical Engineer at Mariana Minerals

- **Company:** Mariana Minerals
- **Location:** San Francisco, CA
- **Compensation:** $100k–$150k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-09-02
- **Last confirmed live:** 2026-09-11
- **Apply:** https://jobs.ashbyhq.com/marianaminerals/3fa2126a-adfb-444c-a3ad-76d0305074da

## Job description

## 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!

## About Mariana Minerals

## Company Overview
- **One-liner**: Mariana Minerals is a software-first, vertically integrated minerals company focused on supplying the minerals critical to modern energy, AI, and defense technologies.
- **Entity Type**: Private (Series A, $85M funding in July 2025)
- **Headquarters**: San Francisco, California, United States
- **Founded**: Not publicly available
- **Founders**: Turner Caldwell (Co-Founder & CEO)

## Core Business
- **Primary industry**: Metal Ore Mining / Critical Minerals
- **Target customers**: B2B – energy, AI, and defense supply chains (including downstream manufacturers and government entities)
- **Mission or purpose**: "Create a future of critical mineral abundance" by reimagining the global minerals supply chain with software, automation, and data-driven decision making.

## Products & Services
- **Copper One (formerly Lisbon Valley Copper Mine)**: World’s first autonomous mine, located in Utah. Produces copper using integrated automation and software control. Restarted production in April 2026.
- **Lithium One**: Lithium project (on the roadmap or early development).
- **Other mineral projects**: Graphite, Uranium, Rare Earth Metals, Cobalt, Nickel, Aluminium – at various stages (stealth or roadmap).
- **CapitalProjectOS**: Internal software platform for capital project management (mentioned in leadership bio).
- **Technology Stack**: React, dbt, TypeScript, Python, TensorFlow, PyTorch, microservices, SCADA, Autodesk, and many others – indicating a strong software engineering backbone.

## Market Standing
- **Valuation/Market Cap**: Not disclosed (private company)
- **Key Metric**: Total funding – $85M Series A (July 2025, 1 investor)
- **Notable Investors/Partners**: Lead investor not publicly disclosed (Andreessen Horowitz was pitched but not confirmed as an investor). Partners include Bot Auto, WeRide, Pronto, Atoms (based on LinkedIn mentions). Also works with UMA (Utah Mining Association).
- **Growth Signals**: Headcount grew 3,575% YoY to 107 employees (as of mid-2026). 73 active job postings. Opened the world’s first autonomous mine (Copper One) in April/May 2026, generating significant industry news and social media engagement.

## Competitive Advantages
- **Software-first approach**: The company builds automation and data systems from the ground up, rather than layering tech onto legacy mining operations. This enables fully autonomous mining.
- **Vertical integration**: They develop, own, and operate mineral projects, controlling the entire value chain from extraction to processing.
- **Deep tech stack**: Use of AI/ML (TensorFlow, PyTorch), simulation, and real-time control systems to optimize mining operations.
- **First-mover in autonomous mining**: Copper One is claimed to be the world’s first autonomous mine, giving them a significant lead in operational efficiency and safety.

## Strategic Focus
- Scale autonomous mining operations beyond copper (lithium, graphite, uranium, etc.)
- Secure domestic supply of critical minerals for U.S. energy, AI, and defense needs.
- Continue aggressive hiring across engineering, operations, and field roles.
- Expand from Utah to additional sites (Houston engineering office, potential new projects).

## Why Work Here
- **Culture principles**: "Extreme Ownership", "Engineer Out Requirements, Then Automate", "Share Your Legos" – emphasizing accountability, simplification, and collaboration.
- **Work environment**: High-growth startup with a mission-driven focus on critical infrastructure. Offices in San Francisco (HQ), Houston (Engineering), and La Sal, Utah (mine site). Hybrid/remote policy not explicitly stated, but multiple office locations suggest flexibility for field vs. office roles.
- **Notable perks**: Opportunity to work on cutting-edge autonomous systems and AI in a traditional industry. Strong engineering culture with modern tech stack (React, Python, ML). Rapid career growth due to company expansion.
- **Talent sources**: Attracts talent from Tesla, Redwood Materials, Lilac, ExxonMobil, Amazon Web Services, and other tech/energy companies – indicating a high-caliber peer group.

## Sources
1. [marianaminerals.com](https://marianaminerals.com/)
2. [marianaminerals.com/careers](https://marianaminerals.com/careers)
3. [marianaminerals.com/about](https://marianaminerals.com/about)
4. [jobs.ashbyhq.com/marianaminerals](https://jobs.ashbyhq.com/marianaminerals)
5. [linkedin.com/company/mariana-minerals](https://www.linkedin.com/company/mariana-minerals)

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