---
title: "Sr. Process Engineer"
company: "Mariana Minerals"
company_url: "https://www.remjobs.works/companies/mariana-minerals"
url: "https://www.remjobs.works/job/mariana-minerals-sr-process-engineer-0da38edb-b4c3-4a16-a663-d4b9007fb381"
apply_url: "https://jobs.ashbyhq.com/marianaminerals/02c135cc-69dd-486e-b56f-defeb3b467f5"
workplace: onsite
location: "San Francisco HQ"
employment_type: full-time
seniority: senior
role: software-engineering
region: united-states
salary: "$120,000–$140,000 per year"
date_posted: 2026-08-17T18:57:33.805Z
first_seen_by_remjobs: 2026-09-05T08:28:22.654Z
---

# Sr. Process Engineer

**Mariana Minerals** · San Francisco HQ

Salary: $120,000–$140,000 per year

Apply: https://jobs.ashbyhq.com/marianaminerals/02c135cc-69dd-486e-b56f-defeb3b467f5

## About Mariana Minerals

Mariana Minerals is a software-first, vertically integrated minerals company focused on supplying the minerals critical to modern energy, AI, and defense technologies.

## About the role

### 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.

### Role Overview

Mariana Minerals is looking for a highly motivated Sr. Process Engineer to join our San Francisco Pilot Plant team. You will lead the design, deployment, and operation of first-of-its-kind refining processes for critical minerals, while also supporting development of software for automated plant optimization. This position is highly hands-on and will play a critical role in bridging R&D and Operations, ensuring processes are robust, safe, cost-effective, and suitable for commercial production.

### What You’ll Do

- Work closely with Pilot Plant Technicians to operate, maintain, troubleshoot, and improve pilot-scale processing equipment

- Design experiments to evaluate process performance, recovery, throughput, and product quality

- Create and maintain key engineering and operational documentation such PFDs, HMBs, P&IDs, Operating Procedures, and Process Control Narratives

- Lead equipment design scopes from concept, through procurement, fabrication, installation, commissioning, and handover to Operations

- Work closely with cross-functional teams including R&D, commercial plant design engineers, project execution teams, and more to scale designs from lab to the pilot to production scale

- Work closely with the software and machine learning teams to develop and implement reactor and plant optimization algorithms

- Travel to pilot and commercial sites to drive commissioning, startup, and ramp-up alongside operations & plant design teams

### What You’ll Bring

- B.S., M.S., or PhD in Chemical Engineering or related field

- Minimum of 5 years of experience supporting R&D scale up, pilot plant operation, and/or commercial production in minerals processing, chemicals, specialty materials, oil & gas, or similar industry

- Strong understanding of reaction engineering, solid-liquid separation, leaching, ion exchange, solvent extraction, and/or similar unit operations

- Hands-on experience designing, commissioning, and operating pilot or commercial-scale process equipment

- Ability to design experiments, problem-solve, and analyze complex datasets

- Strong commitment to Health & Safety and experience with risk management, management of change, and hazard assessment

- Excellent technical writing, communication, and teamwork skills

- Comfort working in fast-paced, cross-functional environments

#### 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!**

---

Source: Mariana Minerals's own career page, read by RemJobs. Canonical HTML version: https://www.remjobs.works/job/mariana-minerals-sr-process-engineer-0da38edb-b4c3-4a16-a663-d4b9007fb381