Senior Geologist

The Senior Mine Geologist serves as the primary technical authority for geological interpretation, grade control modeling, and ore characterization at a high-tonnage (~120,000 stpd) open-pit copper mine operating dual process circuits (sulfide concentrator and oxide LSXEW). Reporting to the Chief Geologist, this role bridges field geology execution and strategic resource management, providing direct technical oversight of mine geologists and technicians while owning key deliverables including block model updates, drill program execution, grade reconciliation analysis, and geometallurgical data integration. The Senior Mine Geologist ensures that geological outputs are accurate, timely, and actionable for mine planning and metallurgical optimization.

Duties and Responsibilities

Ore Control and Grade Control Modeling

• Own the development and maintenance of a grade control model, integrating pit mapping, blast hole assays, on a rolling basis to support short-range and medium-range mine plans.
• Generate and validate dig polygons and ore/waste boundaries for both sulfide mill feed and oxide leach material, ensuring correct routing based on copper grade, mineralization type, solubility characteristics, and deleterious element thresholds.
• Define and maintain material type classifications with clear decision criteria aligned to metallurgical recovery expectations for both concentrator and LSXEW circuits.

Geological Interpretation and Field Work

• Conduct and oversee detailed pit face mapping, geologic logging, and sampling programs with rigorous documentation of lithology, alteration , structure, and mineralization
• Maintain and update the 3D geological model including lithological domains, structural interpretations, alteration zoning, and mineralization envelopes, ensuring the model reflects current pit conditions and new data inputs.
• Interpret geological data in the context of deposit scale to improve predictive accuracy of grade and material type distributions.
• Identify and communicate geological risk or opportunity stakeholders in advance of mining.

Grade Reconciliation and Data Analysis

• Lead detailed grade reconciliation (F1-F3) comparing resource model predictions to grade control model outputs, plant head grades, and metallurgical recoveries across both concentrator and LSXEW circuits.
• Identify root causes of reconciliation variances (geological, sampling, modeling, or operational) and develop corrective actions to improve predictive accuracy.
• Maintain reconciliation databases and produce regular variance analysis reports for review by the Chief Geologist and site leadership.
• Support resource estimation activities by providing validated geological interpretations, domain wireframes, and valid database.

Geometallurgical Integration

• Collaborate with Metallurgy, Process Engineering, and LSXEW teams to characterize ore variability and its impact on plant performance, including hardness, flotation response, acid consumption, and copper solubility.
• Support Mine to Mill initiatives by identifying and communicating rock mass characteristics that influence fragmentation, handling, and throughput to Drill and Blast and Processing teams.
• Contribute to the development and maintenance of geometallurgical models linking geological attributes (mineralogy, alteration, oxidation) to processing outcomes.
• Ensure ore routing decisions are supported by adequate characterization data including sequential copper analysis, mineralogical spot checks, and metallurgical test work results.

Technical Compliance and Reporting

• Ensure all geological data, models, and documentation conform to U.S. SEC SK-1300 technical reporting requirements and international best practices.
• Maintain organized, auditable geological databases and model archives with version control and change documentation.
• Prepare technical memoranda, geological summaries, and supporting documentation for resource updates, mine plan reviews, and regulatory submissions.
• Provide geological inputs for slope stability assessments, waste characterization programs, and environmental permitting as required.

Team Development, Safety, and Collaboration

• Provide day-to-day technical mentorship and supervision of mine geologists and geological technicians, including training on mapping standards, logging protocols, modeling workflows, and QA/QC procedures.
• Serve as acting lead for the geology team during the Chief Geologist's absence.
• Participate in and contribute to daily, weekly, and monthly production and planning meetings, presenting geological findings and recommendations.
• Promote and adhere to all site health, safety, and environmental standards, ensuring geological

Required

• Bachelor's degree in Geology, Geological Engineering, or closely related discipline.
• Minimum 5 years of progressive experience in open pit mine geology, with demonstrated competence in grade control, geological modeling, and reconciliation at copper operations.
• Proficiency in Leapfrog Geo, Hexagon MinePlan (or equivalent) for building and maintaining operational geology models.
• Working knowledge of complementary mine planning and data management software such as MinePlan, Vulcan, acQuire, or Hexagon, and GIS.
• Solid understanding of porphyry copper deposit geology, including supergene enrichment, oxide/sulfide transitions, and alteration.
• Working knowledge of both sulfide flotation and oxide heap leach processing fundamentals as they relate to ore characterization and routing.
• Experience implementing and maintaining QA/QC programs for blast hole, RC, and core drilling sample streams.
• Effective written and verbal communication skills, including the ability to produce clear technical documentation and present geological findings to multidisciplinary audiences.
• Valid Arizona driver's license required for site and pit access.
• Willingness to work on a mine site schedule including field rotations and occasional extended hours.

The mine site is located 64 miles southeast of Phoenix and 70 miles northeast of Tucson. We have a robust carpool / vanpool program and encourage employees to participate. Employees save more than 50% of their commuting costs while reading, sleeping or just enjoying the view.

This position offers an excellent low-cost benefits package for medical/prescription/ dental/vision, disability coverage, life insurance and other optional coverage, and 401(k) plan with company match.

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