NATIVE GOLD COMPOSITION AND MORPHOLOGY THROUGH THE MINERAL PROCESSING STAGES AT THE BUČIM COPPER MINE, REPUBLIC OF MACEDONIA

Abstract

The native gold is a common by-product in many Cu-porphyry deposits, although its distribution and chemistry in many deposit remains not well understood. The aim of this paper is to analyze chemistry and morphology of individual gold grain. In this study we examine the gold chemistry and morphology from mineral processin, flotation and tailings from Bučim deposit. Five grains from the mine level, seven aggregates from the material of flotation, nine aggregates from the concentrate, three from the canalletes and four aggregates from the tail were subject of study. Fineness ranging from 805 to 995. Silver is the most common trace constituent in the studied gold grains from 0.27 to 19.24%. The Cu and Fe are common trace constituent that range in average for iron about 2.5% Fe and copper max. 4% Cu. It is noted that iron and coper as impurities are not present in all tested aggregates. Titanium and tellurium are present only in one analyzed gold aggregates (2.82%).  Studied gold grain appear in various morphological forms, characterized by more or less rounded edges. Elongated gold grain with rounded edges have been commonly observed, while  flat and anhedral grains are more rarely found.

Key words: gold grains; chemical composition; morphological forms; mineral processing