Elemental mapping of some collected gold samples from Al-Amar gold mine in Saudi Arabia

Abstract

The mining waste in Al-Amar gold mine is 150 kg a year due to leakage in the extraction process. Studying the textures of gold deposits can be helpful to improve the process of gold extraction. The present work aimed to study the texture, structure, and composition of gold deposits that have different textures and structures using Scanning Electron Microscope (SEM), Electron probe microanalysis (EPMA), and Micro X-ray Fluorescence (µXRF). The ore minerals at different gold deposits were determined and these are pyrite, chalcopyrite, sphalerite, galena, and silica. The contents of Si and Zn in some specific areas are highly indicated to silica and sphalerite minerals, respectively. Additionally, the high contents of Fe and S, as well as some Cu, confirm the presence of pyrite and chalcopyrite minerals. The µXRF technique was used for elemental mapping of S, Si, Ca, Ti, Mn, Fe, Cu, Zn, Pb, and Au. The spectral interference between Zn-Kβ and Au-Lα was found at different pixels and the Au-Lβ was free from interference and used for following the gold in the samples under investigation. The positive correlation between the Au and the elements Zn, Fe, Pb, and Si indicates the existence of the Au element in different minerals as an invisible specks.