* TSX rises 24.90 points, or 0.20 percent, to 12,692.12 * Valeant surges after move to buy Bausch & Lomb * Gold shares climb after bullion price gains By John Tilak TORONTO, May 27 (Reuters) - Canada's main stock index rose in low volumes on Monday, driven by gains in shares of gold producers and in Valeant Pharmaceuticals International after the drugmaker made an acquisition move. A higher bullion price, supported by strong physical demand and a weaker dollar, spurred the rise in shares of gold companies. Valeant said it agreed to buy Bausch & Lomb Holdings Inc from Warburg Pincus LLC for $8.7 billion in cash, a deal expected to transform Valeant into a global leader in eye care. Holidays in the United States, Canada's biggest trading partner, and in the United Kingdom kept investor interest and trading volumes low. About 40 million shares had changed hands on the Toronto market by mid-morning on Monday, compared with a daily average of 324 million in April, according to the TMX Group. "There is no particular news flow to drive the market one way or the other, with gold being the one exception," said Rick Hutcheon, president and chief operating officer at RKH Investments. "Gold is at best in a trading range and at worst topping out," he added. "It will continue to erode in value." The Toronto Stock Exchange's S&P/TSX composite index was up 24.90 points, or 0.20 percent, at 12,692.12. Seven of the 10 main sectors on the index were higher. The materials sector, which includes mining stocks, added 0.6 percent, thanks to the rising gold producers. Goldcorp Inc was up 0.9 percent at C$27.96, and Barrick Gold Corp added 0.9 percent to C$19.87. Valeant shares surged 6.9 percent to C$93.00 after the Bausch & Lomb deal and helped the healthcare group jump 2.7 percent. "It sounds like a good deal," Hutcheon said. "They've been quite the aggressive acquisitor. Presumably it (Bausch & Lomb) makes a good fit." Energy shares gave back 0.1 percent, reflecting a decline in the price of oil. Enbridge Inc lost 1.1 percent to C$47.93 and was the biggest negative influence on the market.