Overview
Kinross acquired a 75% interest in the Kupol project in Russia on February 28, 2007, through the acquisition of Bema Gold. The remaining 25% is held by the Government of Chukotka.
The Kupol deposit is located in the Chukotka Autonomous Okrug of the Far East Region of the Russian Federation. The total distance between the Kupol property and Bilibino, the nearest major city, is approximately 200 kilometres.
The Kupol mine consists of a high-grade gold and silver vein, which remains open along strike. Development and construction of the project, which employs both open pit and underground mining methods, began in 2005. In May 2008, Kinross announced that the mill had begun processing ore and that the Kupol mine had produced its first ounce of gold-silver dore. In 2009, Kupol produced 925koz of gold equivalent at an average cost of sales of $257 per ounce.
Location
The Kupol Property is located 220 kilometers from the town of Bilibino in the Chukotka Autonomous Okrug of the Far East Region of the Russian Federation. The Kupol Property is comprised of a 1766.73-hectare license area.
Geology
The Kupol Property is situated in the Cretaceous Okhotsk-Chukotka volcanogenic belt. The property is underlain by a bimodal sequence of shallow dipping andesite and andesite–basalt flows and pyroclastic units, rhyolite dykes and flow dome complexes. Two principal mineralized systems have been identified at Kupol; the bulk of the mineralization is hosted in a north–south trending dilatant splay off a large regional fault structure of similar orientation. The main Kupol deposit consists of one or more polyphase quartz–adularia quartz veins of an epithermal low sulphidation character that are sporadically cut by rhyolite dykes. Gold and silver mineralization is primarily associated with sulphosalt–rich bands and pods within colloform, crustiform and brecciated veins. The main deposit has been divided into six contiguous zones: South Extension, South, Big Bend, Central, North, and North Extension. Mineralization has been defined within these zones over a strike length of 3.9 kilometers. The Big Bend zone shows the highest grade and most continuous mineralization.
Mineralization
Gold and silver mineralization at Kupol is hosted by colloform to crustiform-banded quartz–adularia veins and polyphase breccias. The predominant gold and silver minerals are electrum, native gold, silver–rich tetrahedrite (freibergite), acanthite, and a variety of sulphosalts. Arsenic and antimony-rich end members of a variety of mineral groups are present reflecting different solution chemistry in the evolution of the deposit and/or zonation in the deposit. Stephanite and pyrargyrite are the dominant sulphosalts. Traces of selenium–bearing sulphosalts and naummannite are present. Coarse bladed stibnite was observed in trench K–53, in the South Extension zone, and in a vein (Vtoryi I) to the south of the tailings basin. Arsenopyrite is reported in petrography and in some of the logging but is generally very fine grained and not readily recognizable in core or hand samples
Mining & Operation
For mine planning and reserves, the veins are classified into six principal continuous and subparallel groups numbered 20, 30, etc. through 70 Veins, starting from the footwall (west side) of the vein system. Vein complications related to the dikes are factored into dilution estimates for the open pit and underground mines.
The mine planning was completed by Bema with assistance from Wardrop Mining and Minerals. The plan and associated economic model for the Probable mineral reserves takes into account metallurgical losses and mine development (both open pit and underground development) required to exploit the reserves at a profit. In addition, the economic model contains the costs to process the ore, manage the operation, and deliver the product for sale. The production schedule has the open pit and underground mines operating at the same time. Mining takes place over a distance of approximately 2.5 km from north to south.
The Kupol deposit is not fully explored, therefore additions to the mine life and mineral reserves are possible based on further exploration and evaluations.
Processing
The Kupol mill is a conventional gold/silver cyanidation plant that incorporates a CCD thickener washing circuit and Merrill-Crowe zinc precipitation because of the high silver ore grade. Cyanide is accomplished with calcium hypochlorite . The mill is designed to have a maximum throughput of 3,191 tonnes per day (at 100% availability) at a grind size of 80% passing 53 microns (averages 3,000 tonnes per calendar day at 94% availability). This equates to an annual throughput of 1,095,000 tonnes per year.
