Characterisation of alluvial gold exploration data to improve gold recovery in Ghana

Abstract

This study uses exploration data to optimise overburden thickness, cut-off grade and stripping ratio at some alluvial gold mines in the Kibi mining district to improve gold recovery in Ghana. The specific objective is to determine sampling location, overburden thickness, gravel thickness, gravel grade and gold contents. Secondary data are from 48 mining blocks at Kwabeng mine and primary data from 20 mining blocks at Kibi goldfields. Data are analysed using basic statistics and binary plots. Gold content varies at constant total gravel section grade, as overburden thickness and gold grade vary at 0.2 m from 0 to 2.0 m and at 0.05 g/m3 from 0.10 to 0.65 g/m3, respectively. Average values of gravel thickness and gravel grade from both sites are 2.1 m and 0.57 g/m3, respectively. Percentage change in gold content only becomes positive after optimum overburden thickness and a cut-off grade of 0.90 m and 0.285 g/m3, respectively, while the stripping ratio is 0.43:1. The spatial plot of gravel grades using the Surfer Software for the Kwabeng deposit presents a unique resource block model. The optimised values can be used to review the resource block model and combining with established improved operational procedures from previous works.