* Raises stake to 82.6 percent
* Secures raw material supplies
* Purchase price not disclosed
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MOSCOW, Oct 16 (Reuters) - Magnitogorsk Iron and Steel Works bought control of Siberian coal miner Belon on Friday, doubling its stake to 82.6 percent to secure stable raw material supplies for Russia's largest steel mill.
Magnitogorsk, or MMK, said in a statement that supplies from Belon's mines would provide the bulk of its coking ful needs, ending the company's isolation as the only Russian steel major without control of its own coal resources.
It did not disclose the purchase price.
"This transaction brings MMK's self-sufficiency in strategically important input materials to a new level," the steel company's majority owner and chairman, billionaire Viktor Rashnikov, said in the statement.
Magnitogorsk is Russia's third-largest steel maker, after Severstal and Evraz Group, and operates the country's largest single steel plant in the city of the same name.
Unlike its peers, MMK was required until now to buy its coking coal on the open market -- an advantage when raw material prices are low, but increasingly costly when they rise.
MMK has gradually built up its stake in Belon after first entering the Novosibirsk-based miner as a minority shareholder. It already owned 41.3 percent of Belon before buying out its partner, Belon General Director Andrei Dobrov, on Friday. Reuters data shows an 82.6 percent stake in Belon would be worth $682 million at current prices. MMK would therefore have paid half of this amount, $341 million, to double its stake if it paid market price.
Magnitogorsk now owns 100 percent of Onarbay Enterprises Ltd, which in turn owns 82.6 percent of Belon Group. The other 17.4 percent of Belon's stock is in free float.
The deal was announced after markets closed in Moscow. Belon closed down 1.9 percent at 20.68 roubles, in line with a 1.8 percent drop on the wider MICEX exchange.
MMK said it would continue to implement Belon's investment programme. The miner produced 5.5 million tonnes of coal last year, including 2.9 million tonnes of coking coal, and posted a net profit of $124 million. Belon is also a steel trader. (Reporting by Robin Paxton; Editing by David Cowell)