Olimpiada Gold Mine, Russia
The Olimpiada mine of Russia is the fourth biggest gold mine in the world.
The mine is located in Severo-Yeniseisk District of Krasnoyarsk Krai region.
Olimpiada is the largest operation of its owner Polyus Gold and represented 39% of the company's total gold output in 2012.
It also represents 37% of the company's total JORC reserves and resources.
The Olimpiada deposit was discovered in the 1970s. Development began in 1986, but full-scale operations commenced only in 1996.
It evolved into a top gold producing deposit with 22t/y to 26t/y of production by 2000.
Olimpiada mine geology and mineralisation
The mine lies within the Late Proterozoic trough of the Yenisey Range, containing orogenic and placer gold deposits.
The basement complex is represented by Early Proterozoic kyanite-staurolite containing quartzite and marble.
Mineralisation occurs in disseminated sulphide form, which is in a sedimentary rock sequence containing carbonate-mica schists along with a carbonaceous shale unit.
The rocks are deformed into northwest-trending linear folds. The average gold grade is 3.5g/t.
Olimpiada gold mine reserves and resources
The Olimpiada open-pit mine has reserves of 32.13 million ounce (Moz) of gold. The combined measured and indicated gold resources are estimated to be 33.55Moz.
Mining activities and ore processing at Russia's Olimpiada mine
Olimpiada mine is an open-pit mine with the ore stock-piled at the surface. Blasting at the mine is conducted using high-energy fuel emulsion explosives. The rock is excavated using electric and diesel hydraulic excavators.
The width of the operating sites is approximately 30m to 100m. The average depth of the pit is expected to increase by 30m to 40m every year.
The sulphide ore from the Olimpiada mine is currently processed at two mills, Mill2 and Mill 3, with a combined capacity of 8.0Mtpa. The mine processed 8.068Mt of ore in 2012. The Mill-1 of the Olimpiada mine processes the ores of Titimukhta mine.
Gravity and flotation concentration method of ore processing is applied at the Olimpiada mine. Bio-oxidation of the flotation concentrate and sorption leaching of the bioleach product are used in the carbon-in-leach (CIL) process.
Gravitation gold is separated from hydrocyclone sands by processing one third of the circulating load to concentrators. The recovered gravity concentrate goes to the primary concentrate separation section, then for smelting.
The overflow from the hydrocyclones goes for sulphide flotation separation. Flotation tailings of Mill No.2 are put to cyanidation and stockpiled at a tailings dam after neutralisation. The flotation tailings of Mill no.3 are not further treated, but rather pumped to the tailings dam.
The flotation concentrate undergoes additional grinding before passing to bio-oxidation. The gold bearing solutions are subjected to electrolysis after carbon desorption, resulting in a cathode deposit. The cathode deposit is roasted and smelted into doré gold.
Upgrades and additions were made to the processing unit for improving the processing efficiency of the sulphide ore.
The additions included the installation of a second cone crusher, metal ware for the fourth hydrocyclone unit and equipment for the oxidation and sorption operations in the hydrometallurgical workshop.
Gold production at the Russian mine
The Olimpiada mine produced 308,000oz of gold during the first half of 2013. It produced 653,000oz of gold with a recovery rate of 73.7% in 2012. Gold produced at the mine is refined by Krasnoyarsk Non-Ferrous Metal Works.
Performance optimisation programme at the gold mine
A performance optimisation programme has been undertaken at Olimpiada as part of improving the operations. The bio-leaching facility was expanded in 2012, under this programme. It helped to increase the production.
The bacterial oxidation plant was expanded by including six reactors, which helped in increasing the mass pull ratio.
The programme also includes installation of the cooling system, full automation of the facility and installation of new bio-oxidation reactor mixers.
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