Name: Varvara hub.
Location: Kostanay region, north-west Kazakhstan.
Ownership: 100%
Brief Description: Polymetal’s first operation in Kazakhstan. The Varvara hub, which has a mine life until 2032, comprises the Varvarinskoye (Varvara), Komarovskoye (Komar) deposits.
Brief History: Varvara was discovered in 1981 in the historic hard-rock gold mining Urals Fold Belt. European Minerals Corporation (later Orsu Metals) acquired the rights to the deposit and subsequently built an open pit mine, a processing plant and other supporting infrastructure.
Openpit mining started in 2006 and the gold circuit of the processing plant started in December 2007, with the copper/gold circuit starting in March 2008.
Polymetal International acquired the mine in 2009 as a standalone gold and copper mine.
Products: Gold-copper concentrate.
Geology/Mineralisation: The mineralised bodies at Varvarinskoye are classic gold/copper skarn types that are primarily contained within the eastern side of the local fault and are associated with the border between geological formations. Copper/gold porphyry is overlain with quartz-sulphide gold veins and scarn to produce very complex and geometrically complicated zones of economic mineralisation. Mineralisation is discontinuous over a strike length of 4 km and is divided into five zones.
The main primary copper mineral is chalcopyrite with some bornite. The gold is mostly in free form and associated with pyrites and other sulphides. A hallow oxidation zone occurs within 10 m to 50 m below the surface. In this part of the Varvara deposit, copper is mostly represented by oxide minerals not amenable to conventional flotation.
Komar is a low-sulphide, quartz-gold deposit located along the contact of the granite intrusion. Mineralisation occurs within the fault zone and consists of steeply dipping quartz-carbonate-micaceous metasomatites hosted by schists. The overall strike length of Komar is about 6 800 m, with individual mineralised zones generally 500 m to 600 m in length and 4 m to 6 m in width. Oxidation depth is limited to 30 m to 50 m below surface.
Reserves: Total proven and probable reserves as at January 1, 2018, were estimated at 55.2 million tonnes with an average gold equivalent grade of 1.7 g/t, containing 2,961Koz of gold equivalent.
Resources: Total measured and indicated resources as at January 1, 2018, were estimated at 36.4 -million tonnes with an average gold equivalent grade of 1.7 g/t, containing 1,810 Koz of gold equivalent.
Mining Method: Ore at Varvara and Komar is mined using conventional openpit truck-and-shovel and drill-and-blast methods.
Major Infrastructure and Equipment: Varvara’s processing facilities are located at one site. Run-of-mine ore is crushed in batches in a jaw crusher, with separate crushed-ore storage for leach and float material. Gold doré and gold/copper concentrate are produced from the two circuits of the single processing plant.
The float ore circuit comprises two-stage milling (semiautogenous mill and ball mill) and conventional flotation. Concentrate is thickened, filtered, packed in big bags and trucked to a railway spur for transport to the offtaker.
The leach ore circuit comprises two-stage milling, conventional carbon-in-pulp leaching, carbon desorption and regeneration, electrolysis and smelting. The ultimate product is gold doré.
Ore containing more than 0.2% copper (float material) is transported to a 1.1-million-tonne-a-year flotation circuit, with the final product being a gold/copper concentrate that is sold to an offtaker.
Ore containing less than 0.2% copper (leach material) is treated by carbon-in-leach (CIL), with the final product of this process being gold doré, which is sold to an offtaker. The CIL facility has a capacity of 3.15-million tonnes a year.
Prospects: Mining activity continues to shift towards Komar as several openpits at Varvara have been completely mined out.
Further extensions at the Varvara hub are expected as a result of pit enlargement and additional exploration activities, particularly at Komar.
Contact Details:
Polymetal International
Tel +7 812 334 3666
Fax +7 812 753 6376
Email pr@polymetal.ru
Website https://www.polymetalinternational.com