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Mariana Minerals is a software-first, vertically integrated critical minerals company headquartered in San Francisco, California. Founded in 2024, the company designs, builds, and operates its own domestic mining and refining operations to produce battery-grade lithium, copper cathode, and nickel essential for energy, AI, and defense infrastructure. At the core of its business is MarianaOS, an in-house software suite combining autonomous fleet systems, digital twin geologic modeling, dynamic process control, and LLM-powered capital project management platforms (CapitalProjectOS, MineOS, PlantOS) designed to accelerate commissioning timelines and reduce steady-state operating costs.

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.

Job Summary:

We are seeking a dependable and self-motivated Custodian / General Laborer to support the cleanliness, maintenance, and overall functionality of all site buildings and grounds. This role is essential to creating and maintaining safe, organized, and professional workspaces across the operation. The ideal candidate will take pride in their work, demonstrate strong organizational skills, and be flexible in supporting a variety of labor needs across departments.

Key Responsibilities:

1. Facility Cleaning & Upkeep

  • Perform daily and scheduled deep cleaning of all site buildings, including offices, restrooms, break areas, and common spaces.

  • Maintain cleanliness standards through sweeping, mopping, dusting, trash removal, and sanitization.

  • Monitor and restock cleaning supplies and facility consumables.

  • Identify and report maintenance needs or safety hazards promptly.

2. Grounds Maintenance & Landscaping

  • Conduct routine landscaping tasks including weed control and snow removal as needed.

  • Maintain outdoor areas to ensure a clean, safe, and professional appearance.

  • Operate landscaping tools and equipment safely and efficiently.

3. General Labor Support

  • Assist with leach pad labor, EW harvest activities, and maintenance shop organization.

  • Clean up around the Process Plant and other work areas to maintain a safe environment.

  • Support other departments with general labor tasks as needed.

  • Follow instructions from supervisors and collaborate with team members to complete tasks safely and efficiently.

4. Ownership & Safety

  • Take ownership of assigned areas and responsibilities, ensuring high standards of cleanliness and order.

  • Demonstrate initiative in identifying and addressing areas needing attention.

  • Follow all site safety protocols and contribute to a culture of safety and accountability.

Required Skills & Experience:

  • High school diploma or equivalent preferred.

  • Ability to work independently and manage time effectively.

  • Strong attention to detail and pride in maintaining clean, organized spaces.

  • Basic knowledge of cleaning products, tools, and safety procedures.

  • Ability to lift up to 50 lbs and perform physical labor in various weather conditions.

  • Valid driver’s license.

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!

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