Quantifying the variability of a complex ore using geometallurgical domains

Abstract

This comprehensive study focuses on the geometallurgical characterization of the complex Lappberget polymetallic Zn-Pb-Ag-(Cu-Au) sulfide deposit at the Garpenberg mine, one of Sweden’s largest and most significant sources of zinc, lead, and silver. The research explores the intricate mineralogy and texture of the ore, investigating its impact on the variability of flotation performance for different ore types. QEMSCAN® analysis and element-to-mineral conversion (EMC) were employed to quantitatively characterize the ore in terms of mineral distribution and occurrence. The study revealed significant variability in Cu-Pb flotation compared to Zn flotation due to the targeted mineral varieties. While zinc primarily occurred in sphalerite grains, Cu-Pb flotation aimed to recover multiple Pb-, Cu-, Ag- and Au-bearing minerals that were finely grained and intricately intergrown with other sulfides. Grain size and the degree of liberation emerged as primary rate-limiting factors, especially in the Zn flotation circuit. Seven geometallurgical domains were defined based on the concentration efficiencies (i.e., selectivity and recovery) for sphalerite, galena, chalcopyrite, and Ag-bearing phases. The proposed geometallurgical characterization approach aims to transform geologically defined classes into geometallurgical domains by relating the deposit's key mineralogical and textural characteristics to metallurgical performance.