* TSX falls 3.16 points, or 0.02 percent, to 12,669.14 * Six of the 10 main index sectors advance * Potash Corp the biggest negative influence on index * Teck rises after quarterly report By John Tilak TORONTO, July 25 (Reuters) - Canada's main stock index ended narrowly lower on Thursday as jumps in Teck Resources Ltd and Canadian Pacific Railway Ltd and support from gains in commodity prices were offset by disappointing quarterly reports from Potash Corp and Goldcorp Inc . The advances in the price of bullion and other commodities came as the market digested data that showed planned U.S. business spending rose for a third straight month in June, offering a hopeful sign for a pickup in economic growth. "There's a lack of liquidity and perhaps a lack of conviction in the recent moves," said Matt Skipp, president of SW8 Asset Management. Concerns about lack of sustained economic growth in China and fears of a significant slowdown in resource markets are weighing on Canadian stocks, he added. Teck was a big source of support on Thursday, rising 3 percent to C$24.41. The diversified miner reported a drop in second-quarter earnings on lower copper and coal prices. But it also cut its capital spending plan through 2014, delaying new mining projects, a move seen helping it preserve cash. "Teck's having a nice bounce," Skipp said. "It's getting a relief rally based off people nervous about coal and coal shipments, and the quarter in general." The Toronto Stock Exchange's S&P/TSX composite index closed down 3.16 points, or 0.02 percent, at 12,669.14. Six of the 10 main sectors on the index were higher. The materials sector, which includes mining stocks, advanced 0.2 percent, with a rise in some gold miners overshadowing the decline in Potash Corp. Many earnings reports were "awful," said Colin Cieszynski, senior market analyst at CMC Markets Canada. "It looks like just about everybody missed." "But it looks as though commodity prices are holding up some of the stocks," he added. Bullion prices added 0.5 percent, helped by a weaker U.S. dollar. Potash fell 2.1 percent to C$38.35, playing the biggest role of any single stock in weighing the index down. The world's biggest fertilizer producer reported a lower-than-expected quarterly profit and cut its outlook as prices for its crop nutrients fell. Goldcorp was down 1.3 percent at C$28.85. The world's largest gold miner by market capitalization posted a second-quarter loss as a sharp drop in the gold price cut into profits and the company recorded a $2 billion noncash impairment charge. Shares of rival Barrick Gold Corp, however, climbed 1.6 percent to C$17.96. Shares of energy producers climbed 0.1 percent. Husky Energy Inc rose 1.9 percent to C$30.15 after Canada's No. 3 integrated oil company reported a stronger-than-expected quarterly profit as production rose and the company realized higher prices. CP Rail rebounded from a decline in the previous session, when its quarterly results disappointed the market. CP climbed 3 percent to $131.26 and had the biggest positive influence on the index.