---
title: 'Staff Process Engineer at Mariana Minerals'
canonical: 'https://feeny.ai/job/staff-process-engineer-mariana-minerals-houston-52chf093pf31'
type: 'job'
last_seen: '2026-09-11'
---

# Staff Process Engineer at Mariana Minerals

- **Company:** Mariana Minerals
- **Location:** Houston, TX
- **Compensation:** $140k–$175k
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-03-24
- **Last confirmed live:** 2026-09-11
- **Apply:** https://jobs.ashbyhq.com/marianaminerals/54b3a115-b569-48ed-a483-f97caf6e7757/application

**Skills:** Process Scale-up, Plant Design, Equipment Design, Commissioning, Pilot-Scale Experimentation, Data Analysis, PFDs, P&IDs, Mass and Heat Balances, Kilns, Furnaces, Ion Exchange, Solvent Extraction, Solid-Liquid Separation, Leaching, Electrowinning, Technical Writing, EHS Compliance, Risk Management, Machine Learning

> The Staff Process Engineer leads the design, deployment, and operation of pilot-scale refining processes for critical minerals. This hands-on role bridges R&D and plant operations, involving equipment design, experimentation, data analysis, and ensuring safe, robust processes for industrial scale-up.

## 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 seeking a highly motivated Process Engineer to support our next-generation minerals processing pilot plant in Houston. You will help design, deploy, and operate first-of-its-kind refining processes for critical minerals. This role is highly hands-on and will play a key role in bridging R&D and plant operations, helping scale technologies from laboratory development through pilot demonstration and ultimately to commercial production. You will work closely with technicians, engineers, and cross-functional teams to ensure processes are robust, safe, and ready for industrial deployment.

## What You’ll Do

- Lead equipment and process design from concept through procurement, fabrication, installation, commissioning, and startup
- Operate, troubleshoot, and improve pilot-scale processing equipment in collaboration with pilot plant technicians
- Design and execute pilot-scale experiments to evaluate process performance, recovery, throughput, and product quality
- Develop and maintain key process documentation including PFDs, P&IDs, mass and heat balances, operating procedures, and control narratives
- Analyze experimental and operational data to identify opportunities for process optimization and scale-up
- Support development of automated plant monitoring and optimization tools in collaboration with software and machine learning teams
- Ensure safe operations by supporting EHS, hazard assessments, risk management, and management of change processes

## What You'll Bring

- B.S., M.S., or PhD in Chemical Engineering or a related field
- 10+ 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, and plant operation
- Strong understanding of relevant unit operations and equipment such as kilns, furnaces, ion exchange, solvent extraction, solid liquid separation, leaching, electrowinning, or similar technologies
- Ability to design experiments, troubleshoot complex processes, and analyze operational datasets
- Strong commitment to Health, Safety, and Environmental compliance
- Excellent technical writing, communication, and teamwork skills
- Comfortable working in fast-paced environments, wearing multiple hats, 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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- [Sr. Technical Recruiter](https://feeny.ai/job/sr-technical-recruiter-mariana-minerals-san-francisco-hr9b2676c4vw) — San Francisco, CA
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