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Operations

Processing

The two hub’s processing facilities: the Omsukchan concentrator (flotation/gravitation) and the Lunnoye processing plant (cyanide leaching/ Merrill Crowe) are linked technologically and controlled as a single production facility.

The Omsukchan concentrator which process ore from the Dukat and Goltsovoye mines, and the Lunnoye processing plant which processes ores from the Lunnoye and Arylakh mines, as well as concentrate from the Omsukchan facility.

Starting 2011 the Group initiated concentrate sales to a third-party off-taker.

Processing

 

Omsukchan concentrator

The Omsukchan concentrator currently operates at full capacity of 1,500 ktpa.

It uses conventional sulphide flotation technology. The sections are designed to treat different types of feedstock. Extensive geotechnological testing is employed to determine the suitability of particular ore for one of the sections and to assist in the selection of the optimum technological parameters. Thickener output is filtered, dried, cooled, and loaded into 1.5 tonne bags. Every big bag is sampled and tested to estimate silver recovery in cyanidation. The concentrate is trucked either for leaching to the Lunnoye plant or to the port of Magadan for further shipment to a third-party off-taker. At the Lunnoye plant, concentrate from the Dukat concentrator is mixed with ore from the Lunnoye and Arylakh mines and processed into zinc precipitate via agitated-tank cyanide leaching and the Merrill Crowe process.

Precipitate from the Lunnoye mill is transported back to the Omsukchan concentrator for drying, homogenisation, sampling and packing. Dry sampled precipitate is shipped to a third-party refinery for toll-refining into doré and subsequent sale.

Lunnoye Merrill Crowe plant

The Lunnoye processing plant uses conventional cyanide leaching technology, with the Merrill Crowe process used to recover silver and gold values from solution. Run-of-mine ore from Lunnoye and Arylakh mines is blended at the ore storage yard and crushed in the jaw crusher. Further processing comprises two stages of grinding (SAG mill and ball mill), slurry thickening, agitated cyanide leaching (nine tanks providing total residence time of 72 hours), counter-current decantation in four stages and the Merrill Crowe process. Wet precipitate is transported to the Omsukchan concentrator for further processing.

Production statistics

Dukat hub contributes 33% to the total Group gold equivalent production or 356 koz of gold eq. (2012).

  6M - 2013 6M - 2012 2012 2011
Waste mined (kt) 809 1,974 3,558 3,647
Underground development, m 22,372 16,028 34,160 22,387
Ore mined (kt) 943 931 1,782 1,644
Open pit 65 204 316 374
Underground 878 726 1,466 1,270
Dukat    
Ore processed (kt) 818 771 1,439 1,432
Gold head grade (g/t) 0.69 0.67 0.7 0.7
Silver head grade (g/t) 412 411 401 383
Gold recovery 83.4% 78.8% 81% 76%
Silver recovery 85.5% 83.0% 84% 77%
Gold produced (koz) 15.5 13.0 25.2 24.9
Silver produced (Moz) 9.4 8.3 15.5 13.6
Lunnoye    
Ore processed (kt) 168 164 333 301
Gold head grade (g/t) 1.1 1.3 1.2 1.3
Silver head grade (g/t) 423 422 411 414
Gold recovery 87.9% 91.6% 90% 92%
Silver recovery 88.8% 87.5% 88% 87%
Gold produced (koz) 5.1 6.3 11.0 11.7
Silver produced (Moz) 2 1.9 3.7 3.4
Total Production
Gold produced (koz) 20.6 19.2 36.2 36.6
Silver produced (Moz) 11.3 10.2 19.2 17.0
Total cash costs/ silver sold ($/oz)* - 12.2 14.7 14.0
Adjusted EBITDA (US$ m)* - 181 125 282

Processing

The two hub’s processing facilities: the Omsukchan concentrator (flotation/gravitation) and the Lunnoye processing plant (cyanide leaching/ Merrill Crowe) are linked technologically and controlled as a single production facility.

The Omsukchan concentrator which process ore from the Dukat and Goltsovoye mines, and the Lunnoye processing plant which processes ores from the Lunnoye and Arylakh mines, as well as concentrate from the Omsukchan facility.

Starting 2011 the Group initiated concentrate sales to a third-party off-taker.

Processing

 

Omsukchan concentrator

The Omsukchan concentrator currently operates at full capacity of 1,500 ktpa.

It uses conventional sulphide flotation technology. The sections are designed to treat different types of feedstock. Extensive geotechnological testing is employed to determine the suitability of particular ore for one of the sections and to assist in the selection of the optimum technological parameters. Thickener output is filtered, dried, cooled, and loaded into 1.5 tonne bags. Every big bag is sampled and tested to estimate silver recovery in cyanidation. The concentrate is trucked either for leaching to the Lunnoye plant or to the port of Magadan for further shipment to a third-party off-taker. At the Lunnoye plant, concentrate from the Dukat concentrator is mixed with ore from the Lunnoye and Arylakh mines and processed into zinc precipitate via agitated-tank cyanide leaching and the Merrill Crowe process.

Precipitate from the Lunnoye mill is transported back to the Omsukchan concentrator for drying, homogenisation, sampling and packing. Dry sampled precipitate is shipped to a third-party refinery for toll-refining into doré and subsequent sale.

Lunnoye Merrill Crowe plant

The Lunnoye processing plant uses conventional cyanide leaching technology, with the Merrill Crowe process used to recover silver and gold values from solution. Run-of-mine ore from Lunnoye and Arylakh mines is blended at the ore storage yard and crushed in the jaw crusher. Further processing comprises two stages of grinding (SAG mill and ball mill), slurry thickening, agitated cyanide leaching (nine tanks providing total residence time of 72 hours), counter-current decantation in four stages and the Merrill Crowe process. Wet precipitate is transported to the Omsukchan concentrator for further processing.

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