Name: Okhotsk hub.

Location: Khabarovsk territory, Russia.

Controlling Company: Polymetal International (100%).

Brief Description: Okhotsk is one of Polymetal’s more mature operations with gold and silver production. The operation has two operating mines – Avlayakan and Svetloye – and several exploration targets – Kirankan, Khotorchan, Kundumi, Levoberezhny and Gyrbykan. In addition, there is the Khakanja 600 000 t/y Merrill-Crowe processing plant and the 1.2-million-tonne-a-year Svetloye heap-leach circuit.

The Svetloye heap-leach operation has become the main source of production and is expected to be the key driver for sustaining production levels in the longer term.

Brief History: The Khakanja deposit was discovered in 1960 and extensive exploration took place from 1963 to 1971. Polymetal acquired the asset in 1998 and construction started in 2000 followed by the launch of mining activities in 2002. The processing plant was commissioned in 2003 with a capacity of 300 000 t/y, which was subsequently expanded to 400 000 t/y in 2005 with the addition of the ball mill, and to 600 000 t/y in 2006.

Polymetal acquired the Svetloye exploration and mining licence in December 2010. A decision was taken in September 2014 to construct and develop the project. Svetloye was finally launched in August of 2016. The current life-of-mine for Svetloye is about six years during which it is expected to deliver more than 500 000 oz of gold.

Products: Gold and by-product silver.

Geology/Mineralisation: The Avlayakan operation is located in volcanic rocks that are largely of intermediate composition, which host the steeply dipping gold- and silver-bearing veins where most of the gold is spatially associated with zones of altered rocks, primarily those of propylites and metasomatites. The host rocks include andesites, tuffs of andesites and, rarer tuffs of dacite. The mineralisation is a gold-quartz of low-sulphide type.

Gold mineralisation at Svetloye is formed by vuggy silica (secondary quartzite) associated with a high-sulphidation epithermal system. Most gold mineralisation is very fine grained and disseminated. Gold-bearing silicification occurs as flat lenses or pods, which outcrop at the surface and have true widths of between 20 m and 120 m. Higher-grade zones are adjacent to breccias. The oxidation zone develops to a depth of 150 m.

Reserves: Total mineral reserves as at January 1, 2018, were estimated at 6.62-million tonnes, with an average gold equivalent grade of 3.3 g/t.

Resources: Total mineral resources as at January 1, 2018, were estimated at 4.49-million tonnes of ore with an average gold equivalent grade of 4.7 g/t, containing 679 000 oz of gold equivalent.

Mining Method: Avlayakan is an openpit mining operation. Mining is undertaken by a conventional truck-and-shovel operation, with drilling and blasting of ore and waste. 

Svetloye is an openpit mining operation. Mining is undertaken by conventional drill-and-blast and truck haulage.

Major Infrastructure and Equipment: Okhotsk comprises the Khakanja 600 000 t/y Merrill-Crowe processing plant and the recently launched 1.2-million-tonne-a-year Svetloye heap-leach circuit, which is set to become the key driver for sustaining production levels in the long term. 

Prior to processing, run-of-mine ore is crushed in the jaw crusher and is followed by three stages of grinding – semiautogenous mill, one first-stage and two second-stage ball mills – slurry thickening, agitated cyanide leaching, countercurrent decantation in four thickeners and the Merrill-Crowe process. The precipitate is then dried, homogenised, sampled, packed and shipped to third-party refineries for toll processing into doré bars, which are then sold. 

Prospects: Exploration continues at the Okhotsk hub, with 48 km of exploration drilling completed in the Okhotsk region in 2017, a 70% increase, compared with that of the previous year.

At Levoberezhny, in-fill drilling has confirmed the continuity of mineralisation and the option of using heap leaching to extract gold.

An estimated 12.8 km have been drilled at Kundumi within the central and western ore zones, which has resulted in a material increase in mineral resources. The company plans to undertake an additional 15 km of core drilling targeting resource-to-reserve conversion and further resource growth.

At Khotorchan and Gyrbykan, multiple new veins have been discovered. Polymetal plans to complete  resource  definition  drilling  and  start  openpit  mining  on  previously discovered veins in 2018.

Contact Details:
Polymetal International
Tel +7 812 334 3666
Fax +7 812 753 6376
Email pr@polymetal.ru
Website https://www.polymetalinternational.com