Abstract
The aim of this study is to determine the phase forms of gold in the oxidation zone of the Arkharly deposit and to assess their influence on the efficiency of gold and silver recovery. The main research methods included mineralogical analysis, electron microprobe studies, and technological testing. The study identified and characterized silver halides, established their genetic relationship with gold, and substantiated the role of supergene processes in the redistribution of gold. The Arkharly gold-silver deposit (Kazakhstan) is characterized by a complex composition of ores and a variety of gold occurrence forms, which significantly affect processing efficiency. This paper examines the phase forms of gold in the oxidation zone and their impact on technological recovery indicators. Based on mineralogical, electron microprobe, and technological studies, it was found that gold occurs in various forms: native gold of different fineness, electrum, as well as finely dispersed particles associated with silver minerals. Particular attention is given to silver halides, widely developed in the oxidation zone and forming complex intergrowths with native silver and gold. Textural and structural features of mineral aggregates indicate the redistribution of gold under supergene conditions. The formation of gold-bearing phases is associated with chloride and, presumably, colloidal migration of matter, leading to the formation of zonal structures and inclusions of high-fineness gold. Technological test results showed low efficiency of gravity concentration due to the fine-dispersed nature of gold, and high efficiency of cyanidation and sorption leaching (gold recovery up to 93.5%). A direct relationship between the phase forms of gold and recovery indicators has been established. The obtained results expand the understanding of gold behavior in the oxidation zone and can be used in developing effective technologies for processing complex gold-silver ores.