ABSTRACT Two types of gold‐bearing ore are identified at the Shiraldjin deposit (Kyrgyz Republic): (1) a sulfide‐rich ore (approx. 60%), containing coarse native gold particles (> 70 μm); and (2) an ore type dominated by Fe oxides and hydroxides (approx. 80%) with finely disseminated gold. The latter is considered refractory owing to its complex mineral composition and, in particular, the fine intergrowth of gold with iron and manganese phases. Impurities such as manganese (up to 10%), copper, and bismuth hinder gold extraction by conventional methods. Mineralogical studies have revealed that fine gold particles are frequently encapsulated within goethite and pyrolusite, while copper occurs both as dispersed secondary oxides (e.g., malachite, cuprite) and as sulfides (chalcopyrite, chalcocite) with intergrown textures. These minerals possess similar physical properties (e.g., density and surface characteristics), making selective separation by gravity or flotation inefficient. Technological constraints are outlined, and approaches are proposed, including a combination of gravity pre‐concentration, bacterial leaching, and selective flotation as a practical strategy for enhancing gold recovery from complex oxide ores.
Nogaeva et al. (Wed,) studied this question.