Exploration and grade control of zinc ore

Importance of the Topic

Zinc holds a key position as the fourth most utilized metal globally, with sphalerite (ZnS) supplying the majority of production. Rapid, on-site elemental analysis is crucial for efficient exploration and grade control, enabling immediate geological decisions and reducing delays associated with laboratory testing.

Objectives and Study Overview

This study assesses the Thermo Scientific Niton XL5 Plus handheld XRF analyzer for measuring zinc, lead, copper, and silver concentrations in ore samples. Results from field measurements are compared against reference laboratory data obtained by atomic absorption spectrometry (AAS) to validate accuracy and suitability for mining applications.

Methodology and Instrumentation

Measurements were conducted in two modes: direct “point and shoot” screening on the rock face and quantitative analysis of prepared powder samples. Prepared samples were dried, ground, and packed into standard XRF cups with 4 µm polypropylene film. Analysis employed the Mining Mode with three sequential beam settings (Main Range, High Range, Light Range) for a total of 90 seconds per sample. A simple post‐calibration adjustment was applied using reference materials.

Used Instrumentation

• Thermo Scientific Niton XL5 Plus handheld XRF analyzer featuring a 5 W/50 kV X-ray tube and silicon drift detector with graphene window.
• XL5 Mini Test Stand for stable sample cup measurements.

Main Results and Discussion

Field measurements correlated strongly with AAS laboratory values for Zn, Pb, Cu and Ag, showing R² values above 0.99 and slopes near unity, indicating minimal systematic error. Silver at low concentrations (~10 ppm) was accurately quantified. The XRF method also provided semi‐quantitative data on light elements, aiding mineralogical interpretation.

Benefits and Practical Applications

• Provision of real‐time assay data to guide drilling and sampling decisions.
• Substantial reduction in samples sent to external laboratories.
• Improved grade control and ore‐waste discrimination on site.
• Time and cost efficiencies in exploration and mining operations.

Future Trends and Potential Applications

Advances in detector sensitivity, data analytics, and AI integration are likely to enhance handheld XRF capabilities, enabling automated geochemical mapping, predictive modeling for drill targeting, and expanded detection of trace and critical elements such as rare earths.

Conclusion

The Niton XL5 Plus analyzer combines portability with laboratory‐grade accuracy, delivering actionable geochemical data in real time to support zinc ore exploration and mining. Its performance aligns closely with traditional lab techniques, offering a powerful tool for improving operational efficiency and decision making.

References

• International Lead and Zinc Study Group. The World Zinc Factbook 2020, www.ilzsg.org