Endeavor

Endeavor is a producing underground zinc-silver-lead mine located 40 km north of Cobar, New South Wales, Australia, owned by Polymetals. The mine operated from 1982 to 2019, producing over 32 Mt of ore, and currently hosts a JORC resource of 16.3 Mt at 8.0% zinc, 4.5% lead and 84 g/t silver. On August 5, 2024, Polymetals released an optimized restart plan outlining a 10-year mine life producing 10.6 Moz silver, 260 kt zinc and 90 kt lead. The study outlined a pretax NPV8% of A$414 million, IRR of 345%, and projected capex of A$28 million. To fund the restart, Polymetals secured US$20 million in debt from Ocean Partners and raised A$35 million in equity. On June 16, 2025, Polymetals announced that production commenced at Endeavor. Following a temporary suspension after an incident in late October 2025, operations resumed in November and Endeavor produced a total of 356 koz of silver, 7,520 tonnes of zinc and 4,402 tonnes of lead in 2025.

Recent updates have focused on the high-grade Upper North Lode, where development was completed in February 2026 and stoping commenced. In its March 2026 update, Polymetals reported that early production reconciliation indicated materially higher silver grades than modelled due to the presence of native silver. During the March 2026 quarter, Polymetals mined 18,384 tonnes of ore from the Upper North Lode, with continuous mining planned at approximately 20,000 tonnes per month for at least 18 months.

Metalla accrued 272 GEOs from Endeavor in 2025.