Russia dam disaster expected to trim coal exports

* Extent of export impact not clear * Impact on lignite but steam coal also affected By Jackie Cowhig LONDON, Aug 28 (Reuters) - A turbine room flood on Aug. 17 at Russia's largest hydropower plant in Siberia will increase coal burn by up to 2 million tonnes a month and reduce coal exports, major Russian exporters said on Friday. "It's too early to say exactly how much exports could fall. Maybe not by too much, but there will be some effect," one of the country's largest coal sellers said. The flood at the Sayano-Shushenskaya plant, run by RusHydro (HYDR.MM: Quote, Profile, Research), forced steel and aluminium plants in Siberia to turn to emergency power. Repairs will cost "billions of roubles" and take several months, the company said [nLH339111]. Russia exports around 64 million tonnes of thermal coal used in power generation per year by sea, plus further tonnages of coking coal for steel-making. Coal-fired power provides vital baseload electricity supply across Russia. Coal plants mostly fuelled by lignite coal which is not exported tend to run at full capacity only through the autumn and winter. Most of the extra 2 million tonnes a month of coal needed will be lignite but around 500,000-600,000 tonnes is likely to be steam coal, which could be exported, exporters said. Domestic prices for steam coal have been higher than equivalent export levels throughout 2009. The extra need for coal is likely to push domestic prices still higher. Exporters who can place more coal domestically rather than into the depressed European market will do so, exporters said. Russia's largest coal exporters are SUEK (Siberian Coal and Energy Co), KRUTrade, Mechel AOA (MTLR.MM: Quote, Profile, Research), MirTrade and traders Glencore. (Reporting by Jackie Cowhig)