Abstract: The post-leaching of silver (Ag) from a non-sulfide lead–zinc (Pb–Zn) ore flotation tailing leach residue in a copper–ammonium thiosulfate solution was investigated. Ag (89.7%) was extracted into the leaching solution under the following conditions: 30 g/l ammonium thiosulfate, 0.5 g/l copper sulfate, 25 °C leaching temperature and 4 h leaching time. On the basis of the experimental results, a fuzzy logic prediction was made. Ammonium thiosulfate, copper sulfate and leaching period were chosen as predictive criteria in this step. The fuzzy prediction model was found to be very consistent with the experimental data (R2:0.9657). Based on these findings, the application of the fuzzy logic prediction approach to the silver dissolution from the leach residue could be considered.