---
title: 'Sr./Staff Pyrometallurgical Process Engineer at Mariana Minerals'
canonical: 'https://feeny.ai/job/sr-staff-pyrometallurgical-process-engineer-mariana-minerals-houston-dpv5c9qyznbb'
type: 'job'
last_seen: '2026-09-11'
---

# Sr./Staff Pyrometallurgical Process Engineer at Mariana Minerals

- **Company:** Mariana Minerals
- **Location:** Houston, TX
- **Employment:** full-time
- **Work type:** onsite
- **Posted:** 2026-09-08
- **Last confirmed live:** 2026-09-11
- **Apply:** https://jobs.ashbyhq.com/marianaminerals/c46e6d45-e7b0-4c6e-a5dd-287aa0db07a1

## 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 Pyrometallurgical Process Engineer to help build the critical minerals supply chain supporting the world’s energy transition. As a Pyrometallurgical Process Engineer at Mariana Minerals, you will lead the development and deployment of first-of-its-kind high-temperature refining and thermal processing systems. You will play a central role in designing, modeling, scaling, and commissioning pyrometallurgical unit operations, while supporting development of software tools for capital project execution and automated plant optimization. Responsibilities include leading equipment and process scopes from concept and modeling validation through detailed engineering, installation, commissioning, ramp-up, and handover to operations.

## What You’ll Do

- Lead pyrometallurgical process scopes from early concept development and thermodynamic modeling through procurement, detailed engineering, fabrication, installation, commissioning, and ramp-up
- Develop detailed heat and material balances for high-temperature process trains, including drying, calcination, roasting, reduction, smelting, converting, slag cleaning, refining, and off-gas treatment
- Design and validate thermal process flowsheets and PFDs/P&IDs for pyrometallurgical circuits, ensuring safety, reliability, and scalability
- Build first-principles thermodynamic and kinetic models for high-temperature reactors and furnaces (e.g., rotary kilns, calciners, electric arc furnaces, submerged arc furnaces, reverberatory furnaces, flash smelters) to support scale-up and commercial deployment
- Model and optimize phase equilibria, slag chemistry, metal recovery, refractory performance, and energy efficiency
- Define specifications and operating envelopes for high-temperature process equipment, burners, power systems, refractory linings, and gas-handling systems
- Identify, evaluate, and implement process improvements to maximize metal recovery, minimize energy consumption, control emissions, and ensure stable furnace operation under varying feedstock chemistries
- Collaborate closely with R&D, lab teams, and pilot-plant engineers to translate bench- and pilot-scale findings into robust commercial pyrometallurgical designs
- Work with environmental and controls teams to design and optimize off-gas handling systems (e.g., cyclones, baghouses, scrubbers, thermal oxidizers, heat-recovery systems)
- Partner with software and machine-learning teams to automate process-engineering workflows and develop advanced control, optimization, and digital-twin models for high-temperature reactors and furnaces

## What You'll Bring

- Strong understanding of engineering fundamentals and demonstrated ability to leverage the understanding to solve challenging problems
- Strong foundation in chemical engineering, metallurgical engineering, or process engineering, with demonstrated ability to apply engineering fundamentals to complex pyrometallurgical systems
- Experience with equipment engineering and design. Including but not limited to:
- Brownfield modifications and upgrades of process equipment (e.g., leach tanks, reactors, filtration systems, solvent extraction circuits)
- Greenfield design of hydrometallurgical unit operations and integrated circuits
- Troubleshooting, evaluation, and optimization of operating pyrometallurgical or chemical-process equipment
- Experience with the following industries and/or production environments:
- Pyrometallurgical mineral processing or metal refining
- Large-scale mining, critical-minerals processing, or battery-materials production
- Industrial chemical manufacturing with complex aqueous/chemical reaction systems
- Engineering, procurement, and construction (EPC/EPCM) firms supporting mining and mineral processing industry projects

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)

## Other roles at Mariana Minerals

- [Sr./Staff Process Engineer - Detailed Engineering and Plant Design](https://feeny.ai/job/sr-staff-process-engineer-detailed-engineering-and-plant-design-mariana-m9xewg6hdcc5) — Houston, TX
- [Industrial Electrician](https://feeny.ai/job/industrial-electrician-mariana-minerals-moab-snerjqgb4qbh) — Moab, UT
- [Sr. Technical Recruiter](https://feeny.ai/job/sr-technical-recruiter-mariana-minerals-san-francisco-hr9b2676c4vw) — San Francisco, CA
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- [Maintenance Mechanic](https://feeny.ai/job/maintenance-mechanic-mariana-minerals-moab-bc9jcgbeg61b) — Moab, UT
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