* TSX down 23.05 pts, or 0.2 pct, at 11,743.31 * Skepticism whether ECB, Fed will meet expectations * No details on action from Geithner, Schaeuble meeting By Jon Cook TORONTO, July 30 (Reuters) - Canada's main stock index fell on Monday, reversing early gains, as mining and energy shares slid on concerns that expected stimulus measures from the United States and Europe may not be enough to shore up their fragile economies. The U.S. Federal Reserve and the European Central Bank both meet this week, and market expectations have been high in recent days that they will act to stimulate economic growth and that the ECB will tackle the spreading euro zone debt crisis. ECB President Mario Draghi said last week the bank was ready to do whatever was necessary, within its mandate, to save the euro. But after last week's optimism, some investors on Monday turned skeptical that ECB policymakers will deliver in line with market expectations when they meet on Thursday, pressuring the euro and checking gains in commodities. "There's a lot of chatter, but not much about how he's (Draghi) going to do it and whether he's going to get the approval from other communities," said Sid Mokhtari, market technician and director, institutional equity research, CIBC World Markets. Shares turned lower after a meeting between U.S. Treasury Secretary Timothy Geithner and Germany's finance minister, Wolfgang Schaeuble, on Monday failed to produce any concrete details about how the euro zone would tackle the debt crisis. Most of Canada's 10 main sectors fell, led by the influential materials sector, which slid 0.3 percent. Top fertilizer producer Potash Corp was the biggest decliner, falling 2.1 percent to C$44.93. Agrium dropped 1.4 percent to C$95.98, and First Quantum Minerals was off 2.3 percent at C$18.18. Ivanhoe Mines Ltd tumbled nearly 4 percent to C$8.44 after Rio Tinto Plc said on Monday it paid about $935 million for 133.6 million shares, or 51 percent of the stock the Canadian miner put up in a rights offering. At 11:47 a.m. EDT (1647 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 23.05 points, or 0.2 percent, at 11,743.31. The index retreated after touching 11,803.78, its highest level since July 5. Canadian energy shares fell 0.3 percent as U.S. oil prices slipped on signs of lower production from OPEC. Oil and gas losses were led by Suncor Energy, down 1.8 percent at C$31.32, Cenovus Energy, which fell 1.9 percent to C$30.96, and Cameco Corp, off 2.9 percent at C$21.44. Canadian Oil Sands Ltd edged down 0.7 percent to C$20.86 after the pipeline company announced after the close on Friday that its second-quarter profit sank 71 percent due to major plant maintenance that reduced production, lower oil prices and higher operating costs. Sentiment also soured after data on Monday showed Spain slid deeper into recession in the second quarter as tough austerity measures took effect both on overall demand and the price consumers have to pay for goods. Canadian financial shares slid 0.2 percent. Toronto-Dominion Bank led losses, falling 0.6 percent to C$78.97. Manulife Financial Corp sank 0.4 percent to C$10.76, as the market anticipated Canada's largest life insurer will likely post a loss for the second quarter when it reports later this week.