Varvara hub

Varvara was first 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 4.2 Mtpa processing plant and other supporting infrastructure.

Open-pit mining commenced in 2006 and the gold circuit of the processing plant became operational in December 2007, with the copper-gold circuit commencing in March 2008. Since reaching commercial production, Varvara has been unable to attain its planned levels of production for a variety of reasons.

After Solidcore acquired the asset, a massive turnaround plan was launched, including the appointment of a new management team and together with Solidcore Engineering, a new mine plan and updated ore reserves estimate. The post-acquisition turnaround plan was successfully completed in 2010. Solidcore made tremendous progress in terms of optimizing the systems and technologies of the extraction process and ore treatment process, resulting in a substantial increase in productivity. Solidcore also implemented a comprehensive system of grade control, which has significantly improved the output quality.

In 2016, in line with its processing hub strategy, Solidcore acquired the Komarovskoye deposit. The asset provides high-grade, open-pittable ounces at lower cash costs that are set to substantially increase production at the Varvara hub.

The mineralized 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 overlaid 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 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.

Based on mineralogy and metallurgical characteristics, all mineralisation is divided into four types based on the degree of oxidation and copper grade:

1. primary gold (copper less than 0.2 per cent.);
2. primary copper (with gold present);
3. oxide gold (copper less than 0.1 per cent.);
4. oxide copper (with gold present).

Types 1 and 3 are processed through the leaching circuit and are known as leach ore. Type 2 is processed through the flotation circuit and is known as float ore. Type 4 is currently stockpiled separately and not processed.

Komarovskoye 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 Komarovskoye is approximately 6,800m with individual mineralised zones generally 500-600m in length, 4-6m in width. Oxidation depth is limited to 30-50m below surface.