* TSX rises 29.57 points, or 0.23 pct, at 12,823.62 * Agrium up 2.9 percent on outlook boost, Potash up 1.7 pct * Methanex jumps on 10-year gas supply deal with Chesapeake * RIM rises on report of Lenovo interest, Apple woes By Solarina Ho TORONTO, Jan 24 (Reuters) - Canada's main stock index held near 18-month highs on Thursday, led in part by U.S. economic data as well as by fertilizer makers Potash Corp and Agrium Inc, which rose after Agrium raised its profit forecast. In the United States, a private survey showed that factory activity advanced at the fastest pace in nearly two years this month, while the government reported the number of Americans filing new claims for jobless benefits hit a five-year low last week. Canadian stocks were also supported by data that showed Chinese manufacturing growth hit a two-year high this month. "When you've got stronger economic growth in the two largest economies in the world, that can help," said Gavin Graham, president at Graham Investment Strategy, even as he noted that it was still a bit simplistic. "Nonetheless, undoubtedly it's the way the market's mind tends to work." The Toronto Stock Exchange's S&P/TSX composite index rose 29.57 points, or 0.23 percent, to 12,823.62, after touching 12,863.47, its highest since Aug. 2, 2011. Eight of the 10 main sectors on the index finished in positive territory. "There's a growing feeling that we're heading in the right direction. The U.S. economy is showing a little bit of life, and that's spilling over into Canada," said Fred Ketchen, director of equity trading at ScotiaMcLeod. Potash was the most influential positive stock on the index, rising 1.7 percent to C$42.63, while shares of Agrium, among the top five weightiest gainers, climbed 2.9 percent to C$113.90. Agrium rallied after it raised its fourth-quarter earnings forecast as strong grain and oilseed prices spurred demand for its fertilizer products over the fall season. Ketchen, noting the activity in Agrium shares over the past few days, said, "People are taking another look at it, thinking maybe it's time to get back in." The overall materials group was down 1.34 percent, however, dragged lower by slumping gold mining stocks, which slipped with the price of the precious metal. Bullion posted its biggest one day drop in three weeks, falling 1 percent after repeatedly failing to break above a key technical resistance. Shares of Research In Motion Ltd also boosted the market, closing up 2.9 percent following Apple Inc's disappointing iPhone sales and after a report that China's Lenovo Group said a bid for the BlackBerry maker was among the options available to boost its mobile business. "RIM is doing better on the back of Apple's misfortunes," said Graham, adding that the Lenovo news was also a key factor. The overall technology sector finished up 1.91 percent. Energy stocks gained 0.7 percent and was the biggest contributor to the market's gains as U.S. crude oil prices rose. Canadian Natural Resources Ltd rose 1.6 percent to C$30.67. Methanex Corp shares climbed 8.2 percent to C$34.88, touching a life high, after it signed a 10-year natural gas supply deal with U.S. oil and gas company Chesapeake Energy Corp. Financials, the index's weightiest sector, added 0.4 percent.