March 27 (Reuters) - Brazilian miner Vale

said in a filing on Wednesday it had signed a contract to buy a

45% stake in Alianca Energia from Cemig GT, a subsidiary of

energy firm Cemig, for 2.7 billion reais ($540.9

million).

The deal would give Vale 100% ownership of the energy

company Alianca Energia, which has assets including seven

hydroelectric plants and three wind units.

"The acquisition of the stake in Alianca Energia is an

important step towards creating an energy platform, potentially

including other energy assets from Vale's portfolio", the miner

said, adding it will seek for potential partners for the

platform once the Alianca deal is closed.

In a separate filing, Cemig said the deal is aligned

with its strategy to sell minority stakes it owns.

($1 = 4.9921 reais)