Kazakhmys operates both underground and open pit mines, and employs a variety of extraction methods depending upon the mine and geological conditions. In 2007 we mined 34 million tonnes of ore with an average grade, or copper content, of 1.2%.
Mined ore is transported for processing at the concentrators. This is a two-stage process of crushing and grinding the ore and then separating the copper from barren rock by means of flotation, using chemical agents. The final substance is a pulp, or concentrate. The copper content of concentrate can vary widely, partly depending upon the presence of other metals. There are ten concentrators, with facilities at Zhezkazgan, Balkhash and the East Region.
The copper concentrate is then pumped or sent by rail to the smelters for further processing. The smelting process refines the copper concentrate using electric smelting furnaces (at Zhezkazgan) and autogenous bath smelting furnaces (at Balkhash). This produces copper plates, known as anodes, which have a copper content of around 98%. As a second stage in the process, the anodes are then further refined in an electro-refinery where they are suspended in an acid solution to produce copper cathode by electrolysis. The cathodes have a minimum copper content of 99.95%. At Zhezkazgan there are facilities for producing copper rod, which is produced to order and is principally sold on the Chinese market.
Gold and silver slimes and zinc concentrate all emerge as by-products in the second stage of the refining process; the by products are then refined using other Group facilities, though a substantial portion of the zinc output is sold as concentrate.
Most of our raw materials and products are transported by rail. We own approximately 1,100 km of railway infrastructure, for transporting material within group sites, which is linked to Kazakhstan’s main national rail trunk lines. The Group owns over 100 locomotives and 1,500 wagons.
Copper and zinc metal from the Zhezkazgan and Balkhash Complexes are transported by rail primarily to Alashankou in China or to the ports of Novorossiysk or St Petersburg in Russia.
Our copper and zinc is sold worldwide for use in various applications, notably in the construction, automotive, aviation and general engineering industries. Copper has exceptional properties for conducting electricity and is extensively used in wiring. Zinc is mainly used to galvanise steel, improving its durability.