First data concerning the silver-polymetallic mineralization on the Prognoz property were obtained in 1968-1971. From 1973 to 1977 additional geological mapping was completed at the property, along with an extensive exploration program. Exploration activities yielded positive results with 11 mineralized zones with high grades of silver, lead and zinc identified. Between 1987 and 1990, the Yanskaya Exploration Expedition carried out additional exploration works, identifying the mineral composition and main parameters of the mineralised zones. From 1990 to 1998, Prognoz was explored by Yangeologia, which conducted further trenching, core drilling, soil and bedrock sampling, as well as geophysical surveying.
Between 2006 and 2008, an intensive in-fill drilling program with with 873 drill holes totaling 78,925 m was completed, confirming the historical trenching and drilling results. In 2009, the property’s first JORC-compliant resource estimate was prepared by Micon. As part of the resource estimate, pilot plant testwork was performed, demonstrating robust silver recovery levels into both gravity and flotation concentrates. Since 2009, the asset was on care and maintenance.
Polymetal entered into the project in 2017, acquiring a 5% indirect stake for US$ 3 million and in 2018 increased its interest to 100%.
The property is located within the Verkhoyansk mobile belt of northeastern Yakutia. Silver-copper-lead-zinc mineralization, represented by quartz-carbonate-sulphide veins, is located in a sequence of sedimentary rocks composed of Triassic sandstones and siltstones. Nine mineralised zones are defined, with Main and Swamp being the largest (strike length of up to 4 km). Mineralized material is partially oxidised with the depth of weathering varying widely dependent on relief and proximity of water table.