Savkinskoye Deposit is the core operating asset of the Company and includes the pit, a crushing and sorting plant, and a heap leaching area, as well as a hydrometallurgical area producing Dore gold bars. Pit development started in 2008, and nowadays the ore processing capacity is around 1 mln. tons of ore per year. The administrative and operating staff consists of 440 people.
The gold ore deposit is located in Zabaikalie Territory, in 400 km to the east of Chita and in 15 km from the Russian-Chinese border. The property is located in Nerchinsko-Zavodskoy District whose administrative center, Nerchinskiy Zavod village, is just 30 km away. The nearest railway stations Dosatuy and Priargunsk are in 120 and 160 km, respectively. The railway stations and the deposit are connected via the year-round hard-surface federal highway Chita-Khabarovsk and the all-weather earth road made by Mangazeya. 6 kV 8-km power transmission line has been established between the property and Mikhailovka - the nearest settlement.
КThe region’s continental climate is characterized by long cold winters and temperatures as low as minus 50°C. Average yearly temperature in the region is 3°C, average January temperature is minus 27°C, and average July temperature is plus 18°C. During winter, the soil freezes through 3-5 meters and thaws only by mid-July. The region is mostly a permafrost area, which is not, however, true for Savkinskpoye deposit, located on a south-facing slope.
The property is located within the polymetallic belt of Western Zabaikalie. The specific nature of the area’s metallogeny is explained by the diverse exogenous and endogenous processes that have been active in the area for a long period – from the Late Riphean till Cenozoic era. The Vendian-Cambrian strata, in the conditions of sea basin, appeared to be favorable for mechanical and chemical accumulation of heavy metals, including gold. The deposit’s geological boundaries are formed by near-contact Lower Cambrian and the Lower Jurassic deposits with predominant ore body localization in the intensively disturbed and weathered Lower Cambrian strata.
The Smirnovsko-Mikhailovsky ore cluster (Pb, Zn, Ag, Fe, Au) located in Nerchinsko-Zavodskoy ore district which contains the Savkinskoye deposit, has both direct and indirect manifestations of gold-quartz-sulfide or gold-quartz low-sulfidation type mineralization present in mineralized zones and (or) stockworks.
Savkinskoye deposit contains the following mineral associations (from the earlier to the later ones):
- sericite-arsenopyrite-pyrite-quartz gold-containing association;
- quartz-polymetal silver/gold-containing association, including the following paragenic mineral associations:
- antimony-barite-carbonate-quartz association;
- arsenopyrite-pyrite-marcasite-kaolinite-carbonate association.
The above mineral associations are specified in their estimated order of generation. Pyrite, arsenopyrite, sphalerite, chalcopyrite and gold nuggets form a number of generations.
The ores at Savkinskoye deposit have been generated as a result of successive deposition of the above mineral associations of which arsenopyrite-pyrite-quartz and quartz-polymetal ones are gold-productive. Mineable gold grades are found at spatial overlay areas of the above mineral associations.
The principal minerals of Savkinskoye deposit’s primary ores are pyrite and arsenopyrite, and the secondary ones are sphalerite, fahlite, galenite and chalcopyrite.
Gold accumulation occurred through the cocrystallization of pyrite and arsenopyrite with the fine-grained gold or, possibly, with larger-grained gold as well, and subsequently, with the minerals of the later polymetallic phase.
The geological survey performed by Vostokgeologia LLC showed that hypergene alteration of the primary ores is mostly evident at Centralny and Severo-Vostochny properties. Such alteration is less evident at the Yugo-Zapadny property where it alternates with hydrothermal alteration and primary ores. Drilling reveals wide presence of hypergene minerals (iron hydroxides and, less often, lead oxides) in the ores of Savkinsky fault zone. The hypergenesis of Savkinskoye deposit’s primary ores results in the generation of jarosite-scorodite-limonite impure formations containing lead oxides in the weathering layer (oxide zone), and in particular, in the subsurface parts of the deposit.
The weathering layer (oxide zone) of Savkinskoye deposit is characterized by the lack of its complete profile (or zones) due to the tectonic activity in the fault zone.
Given the above, the Savkinskoye deposit belongs to the following two genetic types at the same time:
- endogenous gold-quartz low-sulfidation formation (primary ores), and
- exogenous (gold-bearing chemical residue in terrigenous-carbonate formations containing oxide ores).
RESERVES AND RESOURCES
In accordance with the reserve audit by Micon International Limited, Savkinskoye deposit contains three types of ores – oxide, transition (complex) and sulfide ores.
As estimated by Micon International Limited, the oxide ore reserves at Savkinskoye deposit, in accordance with the JORC Code, are:
|Property||Category||Ore, thousand tons||Au, g/t||Au, kg|
|Probable||1 628||1.42||2 303|
|Yugo-Zapadny Property||Probable||1 192||1.17||1 389|
|Total||Proven + Probable||2 834||1.31||3 712|
The resources of all Savkinskoye deposit’s ores, in accordance with the JORC Code, are:
|Property||Category||Ore, thousand tons||Au, g/t||Au, kg|
|Indicated||2 808||1.54||4 315|
|Measured + Indicated||3 109||1.56||4 845|
|Indicated||3 950||1.36||5 388|
|Measured + Indicated||3 950||1.36||5 388|
|Indicated||6 758||1.44||9 703|
|Measured + Indicated||7 059||1.45||10 233|
The type of mining at Savkinskoye deposit is open-pit. At this stage, the Centralny pit is being developed and production preparatory works at Yugo-Zapadny pit are in process. The ore is transported to the warehouse and then to the processing plant located in 2 km away from the pit. The waste dump is located at the distance of 1 km from the pit.
The deposit’s oxide ore is heap leached at the plant with a production capacity of 1 mln. tons per year. Gold extraction ratio in case of heap leaching is 60-70%.
Operating performance of Savkinskoye deposit:
|Gold production (kg)||346||1 055||204%|