* TSX closes up 51.83 points, or 0.4 percent, at 11,905.44 * Banks and energy companies lead rise * First close above 11,900 since early July By Alastair Sharp TORONTO, Aug 15 (Reuters) - Canada's main stock index closed at a one-month high on Wednesday, helped by small gains across its heaviest weighted sectors, but investors took little comfort given a lack of impetus from the United States or China. Heavyweight banking stocks were the biggest advancers, but traders said overall volume was thin. "There is so much uncertainty out there," said Sal Masionis, a stockbroker at Brant Securities. "America is getting over the proverbial wall of worry. Canadians are always more timid." Mixed U.S. data kept investors guessing about further central bank action to stimulate growth. "The economic stuff coming out of the States, that may have an effect, but we are in the summer doldrums and there is not a lot going on," said John Kinsey, a portfolio manager at Caldwell Securities. He said that absence any surprises , Canadian equities were unlikely to move dramatically in either direction through August. The Toronto Stock Exchange's S&P/TSX composite index unofficially closed up 51.83 points, or 0.4 percent, at 11,905.44. That was its first finish above 11,900 since July 7. The index has been unable to muster a move of more than 0.7 percent in either direction over the past six sessions. U.S. consumer prices were surprisingly flat in July for a second straight month, giving the Federal Reserve room for further monetary easing. Moves to kick-start growth in the U.S. economy are closely watched in Canada, which conducts the majority of its trade with its southern neighbor. But indications on monetary policy moves aren't likely until later this month at the earliest, when U.S. central bankers meet for an annual symposium in Jackson Hole, Wyoming. Meanwhile, the resource-focused index also looks to China for signs that the giant Asian economy's appetite for building materials, oil and other commodities remains strong. China's economy faces big headwinds though cooling inflation is giving the government more leeway to maneuver monetary policy, Premier Wen Jiabao was quoted by state media as saying on Wednesday. But this did not seem to surprise investors. "The numbers have been saying that for several months now," Kinsey said. Banks helped with the rise, with Royal Bank of Canada adding 1 .4 p ercent to C$5 2.72 a nd Toronto Dominion Bank also gaining 0.6 p ercent to C$79 .79. Fertilizer companies Potash Corp and Agrium Inc also gained, u p 0.9 percent and 1.9 percent respectively, w ith a rise in grain prices. Gold miners were a mixed bunch as the price of bullion rebounded on hopes for another round of gold-friendly U.S. monetary easing and increased appetite for the metal from a prominent hedge fund manager. Barrick Gold Corp gained 1.1 percent to C$34.26, while Goldcorp Inc slipped 0.6 percent to C$36.24.