Chemical and Mineralogical Studies of Gold-bearing Rock in Iperindo, Ilesha Goldfield, Southwest Nigeria

Abstract

This paper provides chemical and mineralogical studies on Gold-bearing rock ore. The samples used was sourced from Iperindo at Ilesha Local Government Area of Osun state, Nigeria. 500g of the ore was weighed using digital weighing balance. The samples were crushed and ground until 80% passing of 75 µm sieve. The ground ore was blended homogeneously before the analysis while for the ore microscopic study, true fraction representative gold-bearing rock samples were prepared as polished mounts and characterized using Scanning Electron Microscope-Energy Dispersive X-ray (SEM/EDX). X-ray Fluorescence (XRF) was used to determine the chemical composition while identification of the associate mineral phase was done using X-ray Diffraction (XRD) technique. From the optical microscopy and SEM/EDX study, the gold grain was found embedded in the quartz and spotted interlocked in feldspar within a microscopic size level while a fracture type of surface morphology was observed which shows a protuberant quartz-feldspar veins texture. XRD shows the mineral phases of quartz, dolomite, sylvite, annite. The traces of K, Ba and Rb, in this compound shows that the ore is a typical mesothermal gold deposit. Hence, the gold is finely disseminated on the silicate mineral and this characteristic is unsuitable to be processed by physical separation as the microscopic gold will tend to be lost during processing. However, a sustainable processing method such as froth flotation can be proposed to overcome this problem.