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 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

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.