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 how minerals are sourced, refined, and optimized by combining deep industrial expertise with software, automation, and data-driven decision-making. Join us as we build the future of responsible mineral sourcing and supply.

Role Overview

Mariana Minerals is seeking an experienced and detail-oriented Sr. Estimator to lead cost estimation efforts for mining and mineral processing projects. This role is responsible for developing accurate, competitive, and timely cost estimates that support strategic decision-making and project success.

What You’ll Do

• Lead the preparation of detailed cost estimates for mining, processing, and infrastructure projects

• Analyze drawings, specifications, proposals, and other documentation to prepare time, cost, materials, and labor estimate

• Utilize RSMeans data and tools to develop accurate and benchmarked cost estimates

• Collaborate with engineering, procurement, and project management teams to ensure accurate and comprehensive estimate

• Develop and maintain cost databases, benchmarks, and estimating tools

• Identify project risks and opportunities, providing mitigation strategies

• Review and validate subcontractor and supplier quotes

• Participate in bid reviews, value engineering, and project planning sessions

• Provide ongoing cost analysis and support throughout the project lifecycle

• Mentor junior estimators and contribute to continuous improvement initiatives

• Support the PCM and Software Engineering teams in developing operating systems and tools to automate estimating processes

What You’ll Bring

• 7+ years of experience in estimating within mining, heavy industrial, or construction environments

• Strong knowledge of mining operations, materials, and equipment

• Proficiency in RSMeans

• Advanced skills in Excel and data analysis

• Ability to interpret technical drawings and specifications

• Strong analytical, organizational, and communication skills

• Availability to travel 20% of the time to site or Mariana Minerals offices

Preferred

• Experience with EPC/EPCM project delivery models

• Familiarity with mining projects

Why Join Us?

At Mariana Minerals, you’ll be part of a mission-driven team reshaping the way critical minerals are sourced and supplied globally. You’ll have the autonomy to make big decisions, the tools to innovate, and a culture that values ownership, smart automation, and collaboration.

Our culture is built on three principles:

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.

Mariana is an Equal Opportunity Employer. We celebrate diversity and are committed to creating an inclusive environment for all employees. We do not discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, age, disability, veteran status, or any other protected status.