Characterisation of Small-Scale Gold Mining Tailings in the Western Region of Ghana

Abstract

On average, small-scale miners can recover gold ranging from 20% to 70% of the total available gold by the conventional gravity separation methods only. As a result of this, tailings materials from Artisanal Small-Scale Gold Mining (ASGM) operations contain a significant amount of gold, and characterisation of these materials would inform metallurgical decisions concerning reprocessing of the tailings from ASGM. In this study, size-by-size analysis, gold grade, gold deportment, and cyanidation studies were carried out on ASGM tailings samples collected from five different locations (Asankragua, Bogoso, Prestea, Wassa-Akropong, and Tarkwa) in the Western Region of Ghana. Head grades of tailings samples from Asankragua, Bogoso, Prestea, Wassa-Akropong, and Tarkwa were 1.84 g/t, 4.12 g/t, 0.45g /t, 0.17 g/t, and 5.97 g/t, respectively. The 80% (P80) of the tailings materials passed through 1.797, 0.578, 1.636, 3.210, 0.380 mm screen sizes for samples from Asankragua, Wassa-Akropong, Tarkwa, Prestea and Bogoso, respectively, with an average of 1.52 mm. Also, the gold deportment analysis revealed that the highest metal distribution of 42.03% in -106 µm size fraction for samples from Bogoso, followed by 31.0% for Wassa-Akropong, 29.7% for Tarkwa, 27.0% for Prestea, and 22.0% for Asankragua. It was shown after cyanidation test works that the highest gold recovery was 81.5%, 72.3%, 75.3%, 65.6%, and 38.5% for samples from Wassa-Akropong, Asankragwa, Prestea, Tarkwa, and Bogoso, respectively. Cyanidation can thus be employed to get higher gold recovery in ASGM.