|Location||Verkhoyansk, Republic of Sakha, Yakutia. Russia|
|Ore Reserves (JORC)||2H 2020|
|Mineral Resources (JORC)||256 Moz of Ag Eq at 789 g/t, 2% Pb|
Prognoz is the largest undeveloped primary silver deposit in Russia and currently one of the world’s top silver development projects. It comprises a very large high-grade resource of 256 Moz of Ag Eq at 789 g/t, while its annual production is estimated at 20 Moz of silver.
Polymetal envisions a relatively low-capital and fast development approach for the asset that is based on open-pit mining and conventional processing. The investment decision is expected to be taken by Polymetal’s Board of Directors in Q4 2021 after completion of the feasibility study and the ore reserves estimate in the 2H 2020.
In 2018, Polymetal increased its interest in Prognoz to 100% and completed 60 km of in-fill drilling that resulted in an updated JORC-compliant Mineral Resource estimate.
In-fill drilling results exceeded our expectations and strengthened our belief that Prognoz may succeed Dukat as one of the largest primary silver deposits in the world. The new estimate incorporates data from 532 additional diamond drill holes (71,2 km) completed by Polymetal in
The 56 km2 licence area for Prognoz is situated in the Verkhoyansk municipal district of the Republic of Sakha (Yakutia), 444 km north of the regional centre of Yakutsk (population of approximately 300,000) and approximately 220 km southwest of the municipal centre of Batagai (population of approximately 3,700). The site is remote with seasonal access from Batagai by winter-unpaved road. There is no infrastructure at or near the property.
First data concerning the silver-polymetallic mineralization on the Prognoz property were obtained during geological mapping by the Central Geological Survey Expedition from 1968 to 1971. From 1973 to 1977 additional geological mapping was completed at the property, along with an extensive exploration program comprised of soil sampling using two grids (250×100 m and 250×50 m) and 6,500 m of trenches. 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.
- Compared with the previous Mineral Resource estimate completed by Micon in 2009, Polymetal added lead and used higher cut-off grades together with conservative extrapolation parameters to ensure a more robust and reliable estimate. As a result, the new estimate in comparison with the previous one has the following key characteristics:
- Silver equivalent contained totaled 256 Moz at 789 g/t
- Pure silver contained decreased by 19% from 293 Moz to 237 Moz
- Average silver grade increased by 25% from 586 g/t to 731 g/t
- Average vein width increased by 15% from 1.9 m to 2.2 m
- The share of open-pit resources comprises 46%
- The share of resources within the Indicated category increased from 50% to 61%
- The share of resources in two largest veins (Main and Swamp) increased from 73% to 80%
Prognoz Mineral Resource estimate in accordance with the JORC Code (2012) as at 01 August 2018 (see full report)
|Tonnes||Ag Eq Grade||Ag Eq Content|
Notes: Mineral Resources are reported on the basis of a 106 g/t Ag cut-off for the open pit component (within an optimized pit shell, based on a US$ 16/oz silver price), and a 240 g/t Ag cut-off for the underground component (below the pit shell). A Pb price of US$ 2,200/t was used for the metal equivalent calculation only. For more information please refer to press-release.