Laboratory Technician

San Francisco, CA

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.

The Role

The Laboratory Technician runs high-temperature processing equipment in Mariana Minerals' Deep Sea Nodule Lab, where we turn polymetallic nodules from the Clarion-Clipperton Zone (CCZ) into battery-grade nickel, copper and cobalt. This hands-on role prepares feed, operates a rotary kiln, electric arc furnace and induction converter, samples products, and keeps the lab safe and orderly. The role reports to the Process/Metallurgical Engineering lead and works under engineer supervision at first, with a path to independent operation.

What You'll Do

  • Crush, screen, dry, split and weigh nodule and calcine samples; run nodule wash trials

  • Operate the rotary kiln and its off-gas train: condenser, gas analyzers and NaOH impingers

  • Prepare charges, monitor and tap electric arc furnace heats; run box furnace screening melts

  • Run induction converter heats, including crucible pre-heat, pyrite charging, oxygen blows and timed sampling

  • Monitor temperatures, arc power, gas flows and cooling water; respond to alarms and interlocks

  • Verify exhaust fans and scrubbers before hot work; change gas cylinders and maintain scrubber liquor

  • Record run data in batch sheets and spreadsheets: charge weights, temperatures, gas flows, product masses and sample IDs

  • Track samples through shipment to external labs with chain-of-custody records

  • Keep inventory of crucibles, refractories, reagents and gases

  • Perform routine maintenance and minor repairs; support commissioning of new equipment

  • Follow SOPs, lockout/tagout, hot-work and gas-handling procedures, and wear PPE for molten-metal work

  • Inspect safety equipment on schedule and report near-misses and equipment issues promptly

Desired Qualifications

  • Associate degree or technical diploma in chemistry, materials, metallurgy or a related field, or equivalent hands-on experience

  • 2+ years' experience in a lab, foundry, smelter, refinery or similar high-temperature setting

  • Comfort operating furnaces, gas cylinders and pressurized or water-cooled equipment

  • Experience with molten metal handling, tapping or crucible melting is a plus

  • Familiarity with induction, arc or tube furnaces, off-gas sampling or wet scrubbers is a plus

  • Sample preparation for XRF or ICP analysis is a plus

  • Careful record-keeping and working knowledge of Excel

  • Strong safety habits and willingness to stop work when conditions are unsafe

  • Able to lift up to 50 lb (23 kg), stand for long periods, and work near radiant heat, molten material and process gases

  • Medically cleared and fit-tested for respirator use

  • On-site role with standard weekday hours and occasional extended shifts to finish a furnace heat or cool-down

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

Mariana Minerals is a software-first, vertically integrated minerals company focused on supplying the minerals critical to modern energy, AI, and defense technologies. It engineers, builds, and operates mines and refineries using its proprietary MarianaOS platform, which integrates capital project execution, refinery operations, and mine management into a single AI and machine learning stack. The company targets domestic U.S. critical mineral supply for sectors facing supply chain vulnerabilities, including copper and lithium.

Other roles at Mariana Minerals

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Job details

Location

San Francisco, CA

Company

NameMariana Minerals
IndustryArtificial Intelligence (AI)
Team Size3

Funding

Total raised

$400M

Last stage

Series A

Investors

a16z

Founders

TC

Turner Caldwell

CEO & Co-Founder

LinkedIn
JL

Juan Lozano

Co-Founder & CTO

BT

Baker Tilney

Co-Founder & CFO

LinkedIn

What happens next.

No applications, no recruiter spam. Just the intro.

01

Confirm the fit

A few questions to make sure this role is the right shape for you. Two minutes.

02

I pitch you to the company

I write the intro, send it to the founder, and handle the back-and-forth.

03

A meeting lands on your calendar

If they’re a yes, I book the chat. You show up — that’s the whole job-hunt.