Exploration & Mining of Porphyry Deposits Using Thermo Scientific Portable XRF Analyzers

Significance of the Topic

Porphyry deposits represent the world’s largest source of copper, often containing significant gold, silver and molybdenum. Their vast tonnages and low grades demand efficient exploration workflows that minimize cost and time. Portable XRF technology offers immediate geochemical data, enabling more informed decisions during drilling and resource modeling.

Objectives and Study Overview

This study assesses the performance of a Thermo Scientific Niton XL2 GOLDD portable XRF analyzer for core sample analysis at the Miner Mountain alkalic porphyry Cu-Au deposit in British Columbia, Canada. The goal was to compare on-site XRF results with conventional laboratory ICP data and evaluate the technology’s utility in real-time strip logging and hydrothermal zoning.

Methodology and Sampling

• Study Site: Miner Mountain alkalic porphyry Cu-Au deposit hosted in late Triassic–Jurassic trachybasaltic to trachy-andesitic volcanic rocks with sub-volcanic microdioritic intrusions.
• Sampling Protocol: Drill core intervals of 1 – 1.5 m were directly analyzed on site using the portable XRF unit.
• Validation Approach: All samples were also submitted for commercial laboratory ICP analysis to benchmark XRF accuracy for base and pathfinder elements.

Instrumentation Used

The Thermo Scientific Niton XL2 GOLDD portable XRF analyzer was employed to measure copper, molybdenum, gold and other elements. Laboratory analyses were performed by ICP for independent verification of key element concentrations.

Main Results and Discussion

• Data Correlation: Excellent agreement between portable XRF and laboratory ICP assays for copper and associated metals across three representative drill holes.
• Real-Time Strip Logging: On-site logging identified anomalous mineralized intervals, closely matching conventional strip logs and supporting immediate drilling decisions.
• Hydrothermal Zoning: Elemental patterns (elevated K for potassic cores, Ca in propylitic zones, S for sulfides, As for arsenide minerals) effectively delineated alteration zones critical for targeting ore shoots.

Benefits and Practical Applications

• Accelerated Decision-Making: Direct field measurements enable adaptive drill planning without waiting for laboratory turnaround.
• Cost Efficiency: Reduced sample shipment and laboratory fees through on-site analyses.
• Operational Flexibility: Non-specialists can obtain reliable element data, improving exploration team efficiency.

Future Trends and Opportunities

• Integrated 3D Modeling: Seamless incorporation of XRF data into real-time geological models for refined resource estimation.
• Enhanced Element Ranges: Ongoing improvements in detector sensitivity may expand portable XRF to trace and rare earth element analysis.
• Automated Deployment: Potential for drone- or rover-mounted XRF systems to survey challenging terrain and remote areas.

Conclusion

The Thermo Scientific Niton XL2 GOLDD portable XRF analyzer delivers rapid, accurate in-field geochemical data that correlates strongly with laboratory ICP results. Its use in strip logging significantly improves exploration efficiency, cost control and drill program responsiveness in porphyry deposit investigations.

References

John D.A. (ed.) 2010. Porphyry Copper Deposit Model. U.S. Geological Survey Scientific Investigations Report 2010–5070–B. 186 p.