(Adds details on energy sector, updates prices)
* TSX down 18.22 points, or 0.13 percent, to 13,769.99
* Seven of the TSX's 10 main groups fall
TORONTO, May 12 (Reuters) - Canada's main stock index fell slightly on Thursday as losses for some heavyweight financial and mining names dragged, while energy stocks gained with higher U.S. oil prices and as oil sands employees prepared to return to work after a wildfire.
At 10:44 a.m. EDT (1444 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 18.22 points, or 0.13 percent, to 13,769.99. It touched a 10-day high earlier in the session.
Enbridge Inc advanced 1.8 percent to C$51.61 as it restarted a major pipeline and said crews were on site at its facilities in the Fort McMurray region and confirmed its terminals were not damaged by the wildfire.
Suncor Energy Inc would start to fly employees back to its oil sands base plant from Thursday, a union official said. Its shares rose 0.7 percent to C$34.70.
Smaller energy companies saw larger gains, with Birchcliff Energy Ltd rising 5.5 percent to C$5.41, and Nuvista Energy Ltd, up 5.2 percent at C$6.28. The overall energy group climbed 0.4 percent.
Crescent Point Energy Corp rose 5.3 percent to C$21.43 despite reporting a bigger quarterly loss.
U.S. oil prices hit a six-month high, supported by data from the International Energy Agency (IEA) showing tightening supply, in addition to a surprise drop in U.S. crude inventories.
Seven of the index's 10 main groups were in negative territory, although advancers slightly outnumbered decliners and 15 stocks hit fresh 52-week highs versus only one touching a new 52-week low.
The materials group, which includes precious and base metals miners and fertilizer companies, lost 0.4 percent. The financials group slipped 0.1 percent.
Goldcorp Inc fell 2 percent to C$23.58 and Barrick Gold Corp lost 0.9 percent to C$23.49, while Royal Bank of Canada slipped 0.4 percent to C$76.36.
Valeant Pharmaceuticals International Inc fell 5.3 percent to C$32.05. A key figure at a major hedge fund invested in the battered drug company is leaving the fund, its founder said.
Quebecor Inc advanced 3.9 percent to C$35.34 after the regional cable, telecom and media company reported higher quarterly revenue and raised its dividend. (Reporting by Alastair Sharp; Editing by Nick Zieminski)