Process Mineralogy of a Kuroko-Type VMS Deposit: Influence of Ore Texture on Chalcopyrite Liberation

Process mineralogy provides valuable information for understanding the mineralogical and textural characteristics of volcanogenic massive sulfide (VMS) deposits and their influence on mineral liberation. This study investigates the relationship between ore texture and chalcopyrite liberation in massive and stockwork/disseminated copper ore samples from a Kuroko-type VMS deposit in the Eastern Black Sea Region of Türkiye. Whole-rock mineralogy, textures, and mineral intergrowth relationships were characterized using X-ray diffraction (XRD), reflected-light ore microscopy, and field-emission scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (FE-SEM/EDS) mapping. Both ore types contain chalcopyrite, pyrite, sphalerite, and galena as the main valuable minerals, with quartz as the predominant gangue mineral. However, they show distinct textural characteristics. In the massive ore, chalcopyrite occurs as fine-grained aggregates filling fractures in cataclastic pyrite and commonly forms complex intergrowths with adjacent sulfides. In contrast, the stockwork/disseminated ore exhibits a more dispersed sulfide distribution within a quartz-rich matrix. Liberation analyses conducted across six particle size fractions, ranging from −600 + 500 to −38 µm, demonstrate that chalcopyrite liberation increases as particle size decreases. The stockwork/disseminated ore consistently exhibits higher liberation than the massive ore across all size fractions. The highest liberation values were achieved in the −38 µm fraction, reaching 98% for the stockwork/disseminated ore and 90% for the massive ore. FE-SEM/EDS mapping confirms that micron-scale sulfide intergrowths in the massive ore limit complete liberation and contribute to its lower liberation efficiency. These findings highlight the influence of ore texture on chalcopyrite liberation and provide useful geometallurgical information for optimizing the grinding and beneficiation of Kuroko-type VMS ores.