Rupice, which was touted as one of the highest grade, highest margin projects in the world by London-based capital market firm Tamesis Partners in January, is now said to contain 12 million tonnes at 149 grams per tonne silver, 1.4gpt gold, 4.1% zinc, 2.6% lead, 0.5% copper, and 25% barium sulphate at a cut-off grade of 50gpt silver-equivalent.
That is an estimated 58 million ounces of silver, 527,000oz gold, 489,000t zinc and 312,000t lead in the ground.
Almost 80% of the resource is classified as indicated.
Managing director Paul Cronin said Adriatic was positioned as "one of the leading silver developers in the industry".
The resource will be used as the foundation for a prefeasibility study, which will also take into account ongoing metallurgical tests and mining studies, improving last November's scoping study that defined a post-tax net present value of A$916 million, and an internal rate of return of 107%.
The study considered an 800,000tpa operation with a 14-15 year life.
Cronin said the PFS, which was originally expected earlier in the year, would be released within weeks.
Ongoing work at Rupice has continued to intersect high-grade massive sulphide mineralisation with the system remaining open towards the north and down-dip to the south, where it is edging closer to the Jurasevac-Brestic prospect.
Drilling continues in the wider Vares project with two rigs working at Rupice and the Veovaca deposit.
Adriatic shares were steady at $2.39 yesterday, valuing it at $459 million.