Sopka Kvartsevaya was discovered in 1969 and is a low sulphidation epithermal gold and silver deposit. It consists of several linear alteration zones enclosing relatively narrow adularia-quartz and quartz-carbonate veins. The main gold-bearing zone extends for 2.2 km dipping at low to moderate angles. It contains five high-grade shoots with adularia quartz veins, enveloped by a wide halo of alteration, which contains low-grade zones. In addition to native gold, the main carriers are electrum and kustelite.
|Location||Magadan Region, Russia|
|Operating mines||Birkachan, Sopka, Tsokol, Olcha|
|Key exploration projects||Burgali, Yolochka, Irbychan, Nevenrekan|
|Processing||850 Ktpa CIP/Merrill-Crowe (Kubaka), 1 Mtpa heap leach (Birkachan)|
|Reserves (JORC)||1.1 Moz GE, 3.6 g/t average grade|
|Resources (JORC)||0.6 Moz GE, 7.1 g/t average grade|
|Production start date||2010|
|Life of mine||2024|
The Omolon hub, formed in 2009, is one of the most fully realized hub concepts in our portfolio today. The hub comprises of the Kubaka processing plant, five operating mines -Tsokol, Birkachan, Olcha, Oroch, Sopka, as well as several near-mine development projects with high-grade open-pittable reserves and significant long-term potential. All parts of the hub are centred around the 850 Ktpa Kubaka CIP plant, which serves as the processing facility for operating mines in the area and future near-mine feedstock. In addition, the Company operates a 1 Mtpa seasonal heap leaching circuit at the Birkachan mine.
All parts of the Omolon hub are located northeast of the Magadan region in remote and unpopulated areas covered with taiga forest, with only seasonal access. Land transportation between various parts of the Omolon hub is only possible during the winter via unpaved winter roads, some of which have been constructed by Polymetal. Fuel, consumables and spare parts are delivered to Kubaka and Birkachan via a winter road (usually accessible from January to April) and to Sopka, mostly through the port of Evensk during the summer (June to October), which is located in the Sea of Okhotsk.
The history of the Omolon hub starts with the Kubaka deposit, which was first discovered in 1979. The Kubaka processing plant was built in the early 1990’s, and between 1996 and 2006, Kubaka was the largest gold producer in Russia, until the plant was put on care and maintenance due to the depletion of reserves at the deposit.
In 2008, Polymetal acquired the Kubaka plant together with four mining properties: Birkachan, Oroch, Tsokol and Prognozny. Shortly after, exploration activities commenced at Birkachan and Oroch with an objective to determine whether the recommencement of the Kubaka plant would be economically justified. In 2010, the modified plant was restarted and by 2011, a new processing section was launched that 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 M&A activity, coupled with comprehensive near-mine exploration, Polymetal was able to consolidate several additional neighbouring licensed areas with robust transportation infrastructure. As a result, we were able to create a reliable and stable operation with low costs, all centred around one regional processing plant with multiple sources of feedstock.
Tsokol is a highly weathered near-surface vein deposit with almost vertical adularia-quartz veins form a continuous mineralised zone. It was first discovered in 1984. Ore shoots within the vein structure are on average 4 m wide, up to 110 m high and vary in length from 50 to 90 m. The ore is free-milling and is expected to yield gold recoveries of up to 95 per cent.
Oroch was discovered in 1979 and was extensively explored from 1980 to 2005 through diamond drilling. It is located 110 km from Kubaka and approximately 20 km from the Kubaka-Sopka winter road. Oroch is an epithermal gold-silver deposit. The ore bodies are mainly composed of quartz and carbonate. They have a steep dip and an average width of 6 m.
The mining and exploration licence covers an area of 2.5 square kilometers in the Srednekansk district of the Magadan Region and is located approximately 230 kilometres from the Kubaka processing plant. Olcha mineralisation is of the conventional low-sulfide epithermal type, free milling and with very high-grade bonanza-type shoots.
The Birkachan mineralisation is located in a 150 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 up to
The Kubaka plant currently uses only conventional CIP cyanidation technology. Run-of-mine ore is crushed in a jaw crusher, followed by two-stage milling (SAG mill and ball mill), thickening, CIP leaching, desorption, electrolysis, carbon regeneration and doré smelting. This processing option will continue to be utilised in the long term for ores with low silver content, such as ores from the Birkachan and Tsokol mines.
|Ore Reserves||Tonnage, Mt||Gold grade, g/t||Silver grade, g/t||Copper grade, %||GE grade, g/t||Gold, Koz||Silver, Moz||Copper, Kt||GE, Koz|
|Mineral Resources||Tonnage, Mt||Gold grade, g/t||Silver grade, g/t||Copper grade, %||GE grade, g/t||Gold, Koz||Silver, Moz||Copper, Kt||GE, Koz|
- At Olcha, Mineral Resources (including Ore Reserves) increased by 39 Koz of GE as a result of the 2018 exploration campaign.
- At Nevenrekan, 62 Koz of GE were added to Mineral Resources, with the updated estimate now comprising 164 Koz of GE with an average grade of 12.4 g/t. In 2019, the Company plans to complete the delineation of ore body 1 and further prospecting activities aimed at identifying ore bodies under basalt.
- In 2019, Polymetal plans to complete prospecting activities at the north-western flank of the Tsokol property and prepare Yolochka for the start of open-pit mining.