CANADA STOCKS-TSX gains on Potash, banks; gold miners slip

(Adds strategist comment, updates prices to close) By Alastair Sharp TORONTO, April 24 (Reuters) - Canada's main stock index rose slightly on Thursday, helped by a gain in shares of Potash Corp after the company's results beat low expectations and by small increases in heavyweight banking stocks. The upward thrust was offset by declines in major gold miners and an 11.5 percent plunge in Colombia-focused oil company Pacific Rubiales Energy Corp. With the domestic stock market hi