(Adds details, updates prices)
* TSX up 81.9 points, or 0.63 percent, to 13,001.47
* Eight of the TSX's 10 main groups rise
TORONTO, Dec 16 (Reuters) - Canada's main stock index rose on Wednesday as a bump higher in commodity prices boosted mining stocks and investors braced for an expected U.S. interest rate hike from the Federal Reserve.
The overall materials group, which includes gold and base metal miners, fertilizer stocks and others, climbed 2.4 percent.
Valeant Pharmaceuticals International Inc added to its surge on Tuesday, up 4.6 percent to C$156.61 after projecting 30 percent profit growth in 2016.
At 10:36 a.m. EST (1536 GMT), the Toronto Stock Exchange's S&P/TSX composite index was up 81.9 points, or 0.63 percent, to 13,001.47, with eight of the index's 10 main groups in positive territory.
The index on Monday hit its lowest since August 2013.
The country's two main railway stocks gained, pushing the industrials group up 1 percent.
Canadian Pacific Railway rose 1.5 percent to C$174.25 and Canadian National Railway advanced 0.2 percent to C$74.98.
Golf miner Barrick Gold Corp added 5.6 percent to C$10.32 and rival Goldcorp Inc advanced 3.7 percent to C$15.8, as gold futures rose 1.2 percent to $1,075.8 an ounce. Copper prices advanced 0.9 percent to $4,607 a tonne.
The most influential weights on Wednesday included Canadian Natural Resources, which fell 2.7 percent to C$28.87, and Encana Corp, which lost 3.4 percent to C$7.31.
The energy group retreated 1.2 percent, as oil fell on fresh evidence of growing global oversupply.
One of Canada's 10 largest pension fund managers said on Tuesday that beaten-down oil and gas assets were attractive for long-term investors, echoing sentiments expressed by peers.
The Fed will announce the outcome of its policy meeting at 2 p.m. ET (1900 GMT), followed by a press conference by Chair Janet Yellen at 2:30 p.m. (Reporting by Alastair Sharp; Editing by James Dalgleish)