Six Figure Work

Senior/Staff Chemical Process Engineer

Mariana Minerals

Company websitemarianaminerals.com (Mariana Minerals, opens in new tab)

Base salary $140K  to $175K

Employer-published annual base salary, USD. Advertised base range in San Francisco, CA

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  • LocationSan Francisco, CA
  • WorkplaceOn-site
  • Status at last checkSource accepting applications when checked
  • Last checked (17 min ago) · observed since

About this job

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./Staff Process Engineer to work on building the critical minerals supply chain to support the world’s energy transition and to supply metals necessary for technology and AI, energy, mobility, and defense.

As a Sr./Staff Process Engineer at Mariana Minerals, you will lead the development and deployment of state-of-the-art chemical refining processes, while also supporting development of software for capital project execution and automated plant optimization. Responsibilities will include leading process area and equipment scopes from concept through to design, installation, commissioning, ramp, and handover to the operations team.

What You’ll Bring

  • Lead process area and equipment scopes from concept and modeling validation, through procurement, engineering, fabrication, installation, commissioning, and ramp

  • Manage external equipment providers, technology licensors, and engineering companies to deliver fully integrated and functional mineral refining scopes.

  • Build heat and material balances for integrated mineral refineries

  • Develop Process Flow Diagrams (PFDs) and Piping & Instrumentation Diagrams (P&IDs) for mineral refineries

  • Build first-principles-based models of chemical reactors and unit operations to validate and scale-up designs

  • Identify, evaluate, and implement engineering solutions to optimize process designs, confirming functionality and performance under various operating conditions

  • Work closely with cross-functional teams including lab technicians, pilot plant engineers, process engineers, project execution teams, and more to scale designs from lab through to commercial scale

  • Work closely with the software and machine learning teams to automate capital project execution workflows and develop equipment and plant optimization algorithms

What You’ll Bring

  • Strong understanding of engineering fundamentals and demonstrated ability to leverage this understanding to solve challenging problems

  • Strong foundation in chemical engineering, metallurgical engineering, or process engineering, with demonstrated ability to apply engineering fundamentals to complex systems

  • Experience with plant & equipment engineering and design. Including but not limited to:

  • Brownfield modifications and upgrades

  • Greenfield design

  • Evaluation and optimization of operating facilities

  • Experience with the following industries and/or production environments:

  • Industrial manufacturing

  • Large-scale mining or mineral processing, particularly across hydrometallurgy, electrometallurgy, and pyrometallurgy

  • Large-scale chemical production processes

  • Engineering, procurement, and construction (EPC/EPCM) firms

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 on Ashby · View original posting (opens in new tab)

Pay in context

This role's base floor ($140,000) is above 40% of the 2,102 Engineering (non-software) roles in California listed on this site; 82 others list the same floor. Their median floor is $146,200; the middle half runs from $124,000 to $173,750.

Only jobs on this site count, and each one publishes a base salary of $100,000 or more, so this compares six-figure jobs with each other, not with the whole market. Computed Nov 7, 2026.

This range next to 6 other live Mariana Minerals roles with the nearest advertised base floor
Chart as a table
This range next to 6 other live Mariana Minerals roles with the nearest advertised base floor
RolePublished base
Senior/Staff Chemical Process Engineer (this listing)$140K - $175K
Sr./Staff Mechanical Engineer$140K - $175K
Machine Learning Engineer (Autonomy)$140K - $180K
Sr. Software Engineer, Autonomy$140K - $200K
Sr. Software Engineer, Infrastructure$140K - $200K
Mine Planner$140K - $175K
Staff Mechanical Engineer$140K - $190K

Same $100K to $400K scale as every card. All Mariana Minerals roles · How to read the bar

Observed changes

  1. Began meeting the published-salary criteria
  2. First observed on the employer's board
Observed since
Employer-stated posting date
2026-10-26
Where this pay comes from

Location as the employer wrote it: San Francisco HQ

USD 140,000 – 175,000 · 1 YEAR · Salary

Method
Structured pay field published by the employer
Checked
Rule set
us-base-v2

The employer's job board publishes this pay as a dedicated data field. We read the field directly; no interpretation was needed.

What we verified

  • The pay figures come from the employer's own listing, quoted exactly above.
  • The pay is an annual base salary in US dollars with a minimum of at least $100,000.
  • The role was publicly listed on the employer's job board when last checked.

We do not verify what the employer will actually offer, whether the employer is still recruiting for the role, or anything beyond what the employer published. Full methodology.