Improvement of Heap Leaching Practices in Uşak Kışladağ Gold Mine Using Limestone

This study focuses on improving gold recovery from ore samples from the Uşak Kışladağ Gold Mine, specifically those sized -18+0 mm. The ore was crushed below 2.36 mm and mixed with locally abundant alkaline limestone to enhance permeability and gold dissolution efficiency. Permeability tests were conducted on the -18+0 mm and -2.36+0 mm sized ores, with results of 1.28 x 10⁻³ cm/s and 0.62 x 10⁻³ cm/s, respectively. Additionally, the -2.36 mm ore was mixed with various limestone sizes (-18+10 mm, -10+5 mm, and -5+0 mm) at ratios of 15%, 50%, 100%, 150%, and 200%. The best permeability results were observed with the -2.36+0 mm ore and -10+5 mm limestone mixture. Consequently, leaching experiments were conducted with 1:1 and 1.5:1 ratio of the -2.36+0 mm sample mixed with limestone, resulting in gold dissolution efficiencies of 63% and 53%, respectively. Furthermore, bottle-roll tests were performed on -2.36+0 mm and -75+0 μm samples for 48 hours, with gold recoveries of 64% and 83%, respectively.