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By Nichola Saminather
TORONTO, March 8 (Reuters) - Canada's main stock index closed higher on Thursday, with all sectors but one in positive territory, after U.S. President Donald Trump exempted Canada and Mexico from import tariffs on steel and aluminum.
* Trump pressed ahead with a 25 percent tariff on steel imports and 10 percent on aluminum on Thursday, but gave initial exemptions to Canada and Mexico, starting immediately with an unspecified duration. Their continuation depends partly on progress in negotiations to modernize the North American Free Trade Agreement, a senior administration official said.
* The Toronto Stock Exchange's S&P/TSX composite index ended the day up 66.09 points, or 0.43 percent, at 15,538.70.
* Shares of trade-sensitive railroad and auto parts companies recovered. Canadian National Railway Co jumped 1.05 percent to C$95.08 and Martinrea International climbed 4.1 percent to C$15.22.
* Packing tape-maker Intertape Polymar Group and machine manufacturer Linamar Corp were the biggest gainers on the index, rising 8.5 percent and 8.4 percent respectively, after reporting fourth-quarter profits that beat expectations.
* The technology group was the sector with the most gains, rising 1.2 percent.
* Paramount Resources was the biggest decliner on the index, losing 5.5 percent, after posting a fourth-quarter loss that was bigger than expected.
* Other mining companies Ivanhoe Mines, Teck Resources and Franco-Nevada Corp were also among the biggest decliners, hit by a retreat in metal and oil prices.
* Copper futures pulled back 1.8 percent to $6,823 a tonne, while gold futures slipped 0.4 percent to $1,322.7 an ounce. U.S. oil futures fell 1.4 percent to $60.31 a barrel.
* The TSX materials group, which includes precious and base metals miners and fertilizer companies, lost 0.5 percent. The energy group was the next-worst performer, with a 0.16 percent gain.
* Cominar REIT was the third-biggest decliner on the index, falling 5.2 percent after reporting a drop in its quarterly operating revenue.
* Marijuana producer Canopy Growth was the most actively traded stock on the index.
* There were 164 advancing issues and 78 declining ones. Eight were flat. (Reporting by Nichola Saminather Editing by Frances Kerry and James Dalgleish)