* TSX down 22.62 points, or 0.17 percent, at 12,949.41
* Six of the 10 main groups slip
* RIM to report Q1 results after market close
* Greek debt crisis, mixed U.S. data drag on sentiment
By Trish Nixon
TORONTO, June 16 (Reuters) - Toronto's main stock index was lower at midday on Thursday as gold mining shares tumbled and Greece's debt woes cast a pall on market sentiment.
The index's materials group, home to miners, was down 1.07 percent, tracking lower with copper prices, which fell on a stronger U.S. dollar, fears of weak U.S. economic growth, and worries about what will happen if the Greek debt crisis stays unresolved.
Uncertainty over Greece kept safe-haven bullion steady, but prices were off Wednesday's highs, which weighed on gold-mining shares. The index's gold-mining subgroup fell 1.1 percent. [MET/L] [GOL/]
Goldcorp (G.TO) was off 1.60 percent at C$46.01 and was the most influential decliner on the index. Barrick Gold (ABX.TO) fell 0.84 percent to C$42.69, and Kinross Gold (K.TO) dropped 1.59 percent to C$14.87.
Shortly after noon, the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was down 22.62 points, or 0.17 percent, at 12,949.41, after hitting its lowest level in more than six months, 12,885.54, earlier in the day. The last time it was that low was Nov. 30, when it hit 12,883.27.
"The Canadian market is down somewhat, reflecting continuing gloom on major issues on a global basis, after having one pretty decent day two days ago," said Michael Smedley, chief executive of Morgan Meighen & Associates Ltd.
He said one key stock to watch on Thursday was Research In Motion RIM.TO, which was due to report its first quarter results after markets close "in an atmosphere of growing antagonism by the market".
The BlackBerry maker, up 1.19 percent at C$34.87, warned in April that lackluster sales in the United States and Latin America would likely mean lower earnings than in the previous four quarters. [ID:nN28282063]
Mixed U.S. economic data weighed on overall sentiment. A gauge of regional manufacturing activity slumped to a near two-year low in June, suggesting U.S. factories were faltering and overshadowing better than expected readings on the labor and housing markets. [ID:nN16172420]
Escalating tensions in Greece further dented investor confidence, but some hoped that a second debt bailout for Greece would bring an end to this week's market volatility.
"People are pretty confident that we're going to see some kind of resolution by either this weekend or soon because there is no alternative really, they have to accept some kind of austerity," said Barry Schwartz, vice president and portfolio manager at Baskin Financial Services.
International lenders scrambled to save Greece from default as Prime Minister George Papandreou struggled to quell a revolt in his socialist party against EU/IMF-ordained austerity measures. [ID:nLDE75F0TU]
($1=$0.98 Canadian) (Reporting by Trish Nixon and Solarina Ho; editing by Peter Galloway)