overview and location
Centralnoye deposit is located с. 2 km South from the Tailings project. The license for exploration and mining in the area has been acquired by the company in December 2015.
The deposit has been explored in 1970s as a potential extension of Khinganolovo resource base. However Centralnoye has never come into production due to operational increase of Khinganskoye resources that allowed to operate the deposit until 2000s followed by the bankruptcy and closure of mine.
Centralnoye deposit has a similar structure with Berezovskoye and contains ore bodies and zones of rocks hydrothermally altered to metasomitites that are limited by a series of imbricated rhyolite dykes stretched to north-west. The host rocks are altered and unaltered rhyolites. The ore contains tin mainly in a form of cassiterite presented by two forms – cryptocrystalline and crystalline. Ore columns in Centralnoye are dagger-shaped with a multi-hundred metre span of vertical ore mineralization and an abysmally small length across the pitch.
The Centralnoye deposit contains 6 ore zones. Ore bodies of Malakhitovaya and Pridolinnaya zones have commercial potential. The remaining ore zones are poorly explored. However high grades of silver and copper have been detected in these zones (Centralnaya and Brekchievaya). Ore bodies are limited by the crushed zone and distinct outline of distribution of ore chutes with mainly cassiterite-quartz-sulphide composition. The length of ore bodies varies from 15 to 100 meters with an average thickness of 1-2 meters. The bedding of ore bodies in the surface areas is relatively flat (less than 450). Down the dip the ore bodies have steeper bedding up to 900.
The maximum depth of exploration was limited by 400 meters from surface, and the ore bodies is open to depth. Malakhitovaya ore zone exploration included drilling at 20Х80 m grid, surface trenching every 20m, and 4 drifts (every 80 m) intersecting ore bodies down the dip.
The deposit has favourable geotechnical and hydrogeological conditions: hard host rock and low water inflow into the mine. The company can use existing mine shafts for opening of the mine.
«RJC Consulting» Ltd. was commissioned by Khingan Resources Limited to perform the mineral resource estimation for Berezovskoye tin deposit and issue a report in accordance with the JORC Code guidelines (2012). RJC Consulting made a detailed research of historical drilling data and site visit.
The mineral resource base of Malakhitovaya ore zone is 156 thous. tonnes of ore with average grade of Sn is 2,45% and 220 g/t for silver and classified as Inferred Category*. The Company intends to increase the resource base of Centralnoye deposit for at least 1,5 thous.t. of tin by conducting detailed exploration of all of the ore zones and reestimate existing resources by including associated components. The ore from Centralnoye contains more than 30 minerals apart of cassiterite which is fluorite, sphalerite, galena and chalcopyrite. Tin, copper, silver, molybdenum and tungsten present potential commercial interest.
The company proposes the mine design based on ramp access cut-and-fill mining method. Cut-and-fill mining is applied to mining steeply dipping orebodies, in strata with good to moderate stability, and a comparatively high-grade mineralization which is Centralnoye deposit ore bodies. It provides better selectivity and is preferred for orebodies with irregular shape and scattered mineralization, where high grade sections can be mined separately, and low grade rock left in the stopes. The ore is drilled, blasted, loaded and removed from the stope, which is then backfilled with deslimed sand tailings from the dressing plant, or waste rock carried in by LHD from development drives. The fill serves both to support stope walls, and as a working platform when mining the next slice.
According to processing studies conducted in Soviet times 70% of tin recovery to Sn concentrate and 80% of silver recovery to Cu concentrate can be obtained in gravity - flotation circuit. Ore can be processed at the tailings project modular plant.
Underground project is a stand-alone operation at Centralnoye (Malakhitovaya) that mines 104kt at a peak production rate of 51ktpa. The life of mine period is 3 years. The mining fleet will then be relocated to the Berezovskoe mine after production is completed.
Confirmation drilling programme for Centralnoye deposit by underground and surface exploration boreholes. Expected drilling volume is more than 4 thous. meters.
Launch of the underground mining construction operations. The mine design based on ramp access cut-and-fill mining method.
Commisioning of underground mining operations on Centralnoye deposit. Peak production of 51 ktpa is reached in 2nd year