(Adds details, activity, updates prices to close) TORONTO, Feb 20 (Reuters) - Canada's main stock index closed lower on Tuesday, following a mixed session, with weakness among gold mining stocks offsetting gains for the energy group. The Toronto Stock Exchange's S&P/TSX composite index .GSPTSE closed down 13.2 points, or 0.1 percent at 15,439.44. Just three of the index's 10 main groups ended lower.
* The materials group, which includes precious and base metals miners and fertilizer companies, lost 1.0 percent. Osisko
Gold Royalties fell by 8.1 percent, Endeavour Mining was down 4.9 percent and Klondex Mines fell by
* Gold futures fell 1.8 percent to $1,329 an ounce.
* Copper prices declined 0.6 percent to $7,076.5 a
* The energy group climbed 0.4 percent. Crescent Point Energy Corp <CPG.TO gained 3.2 percent and Suncor Energy rose 1.1 percent.
* The price of oil reached a nearly two-week high amid inventory declines at a key storage hub and expectations that top producers could extend cooperation beyond 2018.
* The largest percentage gainer on the TSX was cannabis
producer Canopy Growth Co , which rose 11.7 percent to
$29.60, while the largest decliner was auto parts company
Uni-Select Inc , down 11.8 percent to $22.94. * Among the most active Canadian stocks by volume were Bombardier B , up 5.1 percent to $3.92, Aurora Cannabis
, up 8.2 percent to $10.96, and Canopy Growth.
(Reporting by Matt Scuffham; Editing by Peter Cooney)