Freelance Grade Control Geologist Jobs in Houston, TX

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
Mariana Minerals is seeking a Lead Resource Geologist to support resource development, mine geology, and technical studies across open pit and underground mining projects. This role will contribute directly to geological interpretation, resource modeling, and grade control inputs that underpin mine planning, engineering, and economic evaluation.
In this role, you will work closely with mine planning, mining engineering, and operations teams to ensure geological models are technically sound, practical, and aligned with mining realities. You will apply hands-on experience in nickel and copper systems to support resource growth, model refinement, and operational decision-making across multiple stages of project development.
This role is ideal for a geologist with solid field, modeling, and operational experience who wants to demonstrate technical excellence and impact in a fast-moving, project-driven environment.
What You'll Do
Geological Modeling & Interpretation

• Own geological and mineral resource model governance, including assumptions, documentation, uncertainty, and technical defensibility
• Build, update, and maintain geological and resource models supporting open pit and underground mine designs and economic evaluation
• Interpret lithology, structure, alteration, and mineralization using drilling, mapping, and sampling data
• Define and apply domain-based modeling approaches and geostatistical methods appropriate for Ni and Cu deposit types

Resource Development & Mine Geology Support

• Provide geological inputs to mine planning and scheduling, including ore/waste boundaries, grade trends, and structural controls
• Support grade control strategies and short-term geological models in both open pit and underground environments
• Drive near-mine resource growth through targeting, drill prioritization, and model-driven exploration
• Provide geological inputs to reserve conversion, including modifying factors, dilution assumptions, and model validation

Cross-Functional Collaboration

• Work closely with mine planners, mining engineers, and geotechnical teams to ensure geological models are fit-for-purpose
• Translate geological uncertainty and risk into clear inputs for planning and engineering trade-off decisions
• Support technical study work across conceptual, PEA, PFS, and FS stages

Data Quality & Technical Rigor

• Ensure high standards for geological data quality, QA/QC, and documentation
• Review and validate drilling, sampling, and assay data prior to model incorporation
• Maintain clear assumptions and traceability in all geological deliverables
• Ensure geological and resource work complies with applicable reporting codes (e.g. JORC, NI 43-101, CRIRSCO-aligned standards)

Operational & Field Support

• Define geological objectives, data requirements, and standards for drilling, logging, and sampling, and provide geological oversight of field execution
• Undertake or review field mapping, underground mapping, and face mapping as required
• Support or lead reconciliation of geological and resource models against production data

What You'll Bring

• Bachelor's degree in Geology, Geological Engineering, or a related field (Master's preferred)
• 10+ years of progressive experience in mine and/or resource geology
• Demonstrated experience supporting both open pit and underground mining operations
• Direct experience with nickel and copper mineral systems
• Strong applied geostatistical and mineral resource estimation experience, including domaining, variography, classification, and reporting
• Proficiency with geological modeling and estimation software (e.g., Leapfrog, Datamine, Vulcan, Micromine)
• Strong understanding of geological controls on mineralization and their implications for mining
• Ability to communicate geological concepts clearly to non-geologists
• Willingness to work across office and site environments as needed
• Professional Geologist (P.Geo or equivalent), or eligibility
• Demonstrated leadership of mineral resource estimates under reporting codes (e.g. NI43-101, JORC)
• Experience in greenfield or brownfield exploration programs tied to active mines

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.