Mine tailings management poses a major environmental challenge for the mining industry. The production of silico-aluminophosphate geopolymers has been proposed as a potential upcycling strategy, however, the existing literature is still incipient. This study investigates the production of silico-aluminophosphate (SAP) geopolymers from copper mine tailings via phosphoric acid activation. Copper mine residues have been collected and their mineralogy (XRD) and oxide composition (XRF) characterized. Copper mine tailings have been activated with phosphoric acid at varying liquid-to-solid ratios (0.35, 0.40, and 0.45) and phosphoric acid concentrations (30, 40, and 50 wt%), and cured at different curing temperatures (20 and 40 °C) to investigate the effect of such synthesis factors on the mechanical properties of SAP geopolymers pastes. The strength development of geopolymer pastes have been characterized, and SEM and XRD techniques used to further evaluate the reaction products, morphology and microstructures formed. The results indicate that copper mine tailings can be effectively upcycled through activation with phosphoric acid, demonstrating their potential as alternative raw materials for the development of innovative and sustainable building materials.