Economic By-Products in copper Porphyries: Silver in the Ascutita Cu-Porphyry, Romania

The Ascutita porphyry Cu-Mo prospect is located in the SW Poiana Rusca Mountains, Romania. Current assessment estimates a resource of 110 Mt @ 0.15 % Cu-equivalent. In relatively low-grade deposits such as this, by-products Ag (2–3 ppm) are important determining economic feasibility overall orebody. Assayed Cu and have clear downhole correlation. absence other silver-bearing minerals, or correlations with sulphides (e.g., Pb indicating Ag-bearing galena) this suggests Cu-sulphides instead dominant hosts Ag. Petrography 21 samples from various drillholes show chalcopyrite Cu-sulphide present, spatially associated to two stages pyrite. LA-ICP-MS analysis determined that both Stage 3 pyrite (younger) co-host Chalcopyrite mostly solid solution, whilst within variety complex, sulphosalt micro-inclusions undetectable on an SEM, but apparent time-resolved spectra. These lock Ag, bulk median content 0.79 ppm. also contains mean concentrations 52 ppm Bi 46 Se: typically penalty-incurring elements at smelters. has greater concentration than (median = 30.3 potential for 181 ppm), presumably solution. lattice-bound partitioned into through monovalent, simple substitution Ag+ Cu+. Occurrence main Cu-bearing phase raises possibility combined recovery, study demonstrates value trace element geometallurgical assessments orebodies.