* S&P/TSX composite down 0.66 percent at 11,741.62
* Energy producers hurt by oil below $80 a barrel
* Gold miners fall as bullion slips (Adds details, quotes)
By Claire Sibonney
TORONTO, Jan 13 (Reuters) - Toronto's main stock index fell for a third day on Wednesday as investors continued to worry that China's moves to tighten monetary policy could cut demand for key commodities such as oil and metals.
Shares of Suncor Energy Inc (SU.TO) led the index's decliners, dropping 1.7 percent to C$37.22.
"The commodities are just volatile and they're going to remain to be volatile over the next while," said Bruce Latimer, a trader at Dundee Securities.
At 10:23 a.m. (1523 GMT) the resource-heavy S&P/TSX composite index .GSPTSE was down 78.56 points, or 0.66 percent, at 11,741.62. Eight of the index's 10 main groups were lower, led by a 1.03 percent drop in the energy sector.
Oil fell to its lowest level this year on rising U.S. inventories and concerns about China, dipping below $80 a barrel. [O/R]
Global markets were rattled by China's surprise increase of banks' required reserves, despite the fact that the world's third-largest economy shot back towards double-digit growth from a near standstill in late 2008. [ID:nTOE60C02F]
"(China) had indicated they were going to try to tighten the monetary policy to sort of prevent or restrict the possibility of any asset bubbles happening out there," said Latimer. "Nevertheless, their demand and consumption is rising in the long term and that is strong for commodities
Gold producers were also among the key decliners on the TSX as the metal slid as the U.S. dollar recouped losses against the euro. [ID:nLDE60C0SB]
In earnings news, Cogeco Cable Inc (CCA.TO) and Corus Entertainment Inc (CJRb.TO) both reported higher first-quarter earnings. Cogeco Cable rose 4.5 percent to C$36.28, while Corus fell 0.67 percent at C$19.41. [ID:nN13218325] [ID:nN13218120]
$1=$1.04 Canadian Reporting by Claire Sibonney; editing by Rob Wilson