SECTION I · THE BRIEF
Brief #57463Updated 08 OCT 2026SAN FRANCISCO, CAAshbyKHOSLA VENTURES
Employbl Company Profile

Laboratory Technician

Mariana Minerals is a vertically integrated minerals company that develops and operates mineral projects focused on supplying critical minerals. The company combines mining operations with software and technology…

Location
San Francisco, CA
Company size
100–500
Posted
6d ago
Via
Ashby
Section II · Full ProfileFree with an account
  • 01Comp band & equity packageLocked
  • 02Seniority & experience requirementsLocked
  • 03Interview process & rubricLocked
  • 04Hiring manager & team contextLocked
  • 05Growth trajectory in this roleLocked
  • 06Offer & decision timelineLocked

Free account · no card · 2 minutes

Laboratory Technician

Mariana Minerals· San Francisco HQView company profile


Job title
Laboratory Technician
Job location
San Francisco HQ
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

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!

View job listing ↗
The Saturday Briefing

Get the Saturday tech briefing

New company profiles, funding moves, and who’s hiring across the market — every Saturday morning.

Mariana Minerals headquarters

Houston, TX

Company size

100–500 employees

Founded

2022

Total raised

$395,499,488

View company profile ↗

Work at Mariana Minerals? Claim its Employbl profile