Mineralogical characterization of the Hakkari nonsulfide Zn(Pb) deposit (Turkey): The benefits of QEMSCAN®

The development of relatively simple and low-cost processing technologies such as solvent-extraction, AmmLeach®, leach/solvent extraction/electrowinning and pyrometallurgy, combined with the increase in Zn prices, resulted in an increase in the study and exploration of nonsulfide Zn(Pb) deposits. The Hakkari deposit is an example of a supergene nonsulfide Zn(Pb) deposit located in Southeast Turkey, hosted in brecciated Jurassic limestone. The ore concentrations, mainly consisting of oxidized Zn minerals (smithsonite and hemimorphite) were examined in this study using QEMSCAN®. The formulation of a Species Identification File (SIP) was necessary to discriminate the mineral species. QEMSCAN® analysis allowed detailed mineralogical characterization of several Hakkari drill core samples, building on, and adding to previous studies of the deposit. In particular, the modal mineralogy for the ore and gangue minerals, and mineral association and spatial distribution data of the economic minerals provided information for the advanced exploration phase of the deposit, which could influence the feasibility study and ore processing options. The results show that smithsonite is the main ore mineral, occurring in two generations: one (FeO and PbO bearing) replaces sphalerite and host carbonates, and another (CaO-bearing) is concretionary in cavities. Hemimorphite occurs in cavities or replaces smithsonite in veinlets. Fe-(hydr)oxides can be enriched in Zn, Pb, As and SiO2. Mn-Fe-(hydr)oxides (Pb ≫ Zn enriched) are rare. Remnant sulfides have also been detected. The QEMSCAN® study has confirmed the main mineral phases found in previous studies, but identified other phases not previously detected (e.g. minerals in trace amounts such as sauconite), being also able to distinguish and quantify impure phases (e.g. Zn-dolomite, Cd-calcite), and identify amorphous phases [pyrite/Fe-(hydr)oxides/jarosite mix] that XRD found challenging. Not detecting the detrimental minerals/elements may result in processing problems, penalties at the smelter, poor metal quality, and environmental damage. Thus the use of QEMSCAN® technology on this type of deposit is beneficial for both exploration and potential processing, provided that careful attention is paid to the complex mineralogy and limitation of the analysis technique.