UPDATE 4-Oil major Total to buy Synenco Energy for $471 mln

(Adds environmental review for Joslyn mining project.)

PARIS/CALGARY, Alberta, April 28 (Reuters) - French oil major Total (TOTF.PA: Quote, Profile, Research, Stock Buzz) said on Monday it will buy Synenco Energy Inc (SYN.TO: Quote, Profile, Research, Stock Buzz) for about C$480 million ($471 million), in a deal that will boost Total's holdings in Canada's oil sands region and end Synenco's year-long search for a buyer.

Total will offer C$9 for each Synenco share, which represents a premium of around 15.5 percent to Synenco's closing price on Friday of C$7.79.

Total added that the offer -- just more than half the C$17.50 a share Calgary, Alberta-based Synenco received when it went public in 2005 -- had been unanimously approved by Synenco's board of directors.

Synenco's main asset is a 60 percent stake in the 1.66 billion barrel Northern Lights oil sands project. The remaining stake is held by Chinese refiner, Sinopec (600028.SS: Quote, Profile, Research, Stock Buzz) (SNP.N: Quote, Profile, Research, Stock Buzz).

Synenco said it also has about C$230 million in cash on hand.

The oil sands region of northern Alberta is the world's largest storehouse of oil outside the Middle East.

Production from the region is expected to nearly triple to 3 million barrels a day by 2015 as companies act on plans to invest more than C$100 billion on projects to exploit the resource.

Synenco put itself up for sale a year ago, when the Northern Lights construction budget swelled to C$10.7 billion, nearly double its initial estimate, and it halted plans to build an upgrader to convert the tar-like bitumen into refinery-ready synthetic crude.