Name: Omolon Mining Hub.

Location: The mine is located in the Magadan region of Russia.

Mine Owner/s: Polymetal International.

Brief Description: The hub comprises the Kubaka processing plant, three operating mines – Tsokol, Birkachan and Olcha – as well as several near-mine development projects with high-grade openpittable reserves and significant long-term potential.

All parts of the hub are centred around the 850 000 t/y Kubaka carbon-in-pulp (CIP) plant, which serves as the processing facility for operating mines in the area and future near-mine feedstock.

In addition, Polymental operates a one-million-tonne-a-year seasonal heap-leaching circuit at the Birkachan mine.

The Omolon Mining Hub has a mine life to 2024.

Brief History: The history of the Omolon Mining Hub starts with the discovery of Kubaka deposit in 1979.

The Kubaka processing plant was built in the early 1990s and, between 1996 and 2006, Kubaka was the largest gold producer in Russia, until the plant was put on care and maintenance owing to the depletion of reserves at the deposit.

Polymetal acquired the Kubaka plant in 2008, together with the Birkachan, Oroch, Tsokol and Prognozny mining properties. Shortly thereafter, exploration activities started at Birkachan and Oroch to determine whether the restart of the Kubaka plant would be economically feasible.

The modified plant was restarted in 2010 and by 2011 a new processing section was launched, which enables the plant to process ores with high silver content. The plant now includes a new leaching circuit, counter-current decantation and a Merrill Crowe circuit.

As a result of a rigorous approach to merger and acquisition activity, coupled with comprehensive near-mine exploration, Polymetal has been able to consolidate several additional neighbouring licensed areas with robust transportation infrastructure.

Primary Metals/Minerals: Gold.

Secondary Metals/Minerals: Silver and copper, as well as some platinum-group metals.

Geology/Mineralisation: The Tsokol deposit was first discovered in 1984. It is a highly weathered near-surface vein deposit with almost vertical adularia-quartz veins, which form a continuous mineralised zone. Ore shoots within the vein structure are on average 4 m wide, up to 110 m high and vary in length from 50 m to 90 m. The ore is free-milling and is expected to yield gold recoveries of up to 95%.

The Olcha mining and exploration licence covers 2.5 km2, in the Srednekansk district of the Magadan region, and is located about 230 km from the Kubaka processing plant. Olcha mineralisation is of the conventional low-sulphide epithermal type, free milling and with very high-grade bonanza-type shoots.

The Birkachan mine mineralisation is located in a 150-m- to 200-m-wide zone. The mineralisation comprises two distinct types – gold/silver veins and disseminated stockwork. The individual veins generally have an average width of  2 m to 8 m, extend up to 200 m to 250 m along strike and down-dip and carry gold grades from 8  g/t to 14 g/t. The stockwork comprises mineralised zones of 60 m to 80 m thick, extending 2.5 km along strike and 150 m to 200 m down-dip from the surface and grading 1 g/t to 3 g/t of gold.

Reserves: Total proven and probable reserves as at January 1, 2020, were estimated at 5.8-million tonnes grading 4 g/t gold equivalent.

Resources: Total mineral resources as at January 1, 2020, were estimated at 1.6-million tonnes grading 10.4 g/t gold equivalent.

Mining Method: Openpit/underground.

Major Infrastructure and Equipment: The hub comprises three mines, and the Kubaka processing plant.

The plant currently uses only conventional CIP cyanidation technology. Run-of-mine ore is crushed in a jaw crusher, followed by two-stage milling (semiautogenous mill and ball mill), thickening, CIP leaching, desorption, electrolysis, carbon regeneration and doré smelting. This processing option will continue to be used in the long term for ores with low silver content, such as ores from the Birkachan and Tsokol mines.

Prospects: Polymetals has shifted its attention towards safer methods of waste storage, particularly dry stack tailings. This technology significantly reduces the probability of dam failure and minimises potential damages in the event of an accident. It is already in operation at Amursk and Voro , and will be extended to Nezhda, Prognoz, POX-2 and Omolon.

Contact Details:
Polymetal International
Tel +7 812 334 3666
Website https://www.polymetalinternational.com