Dec 9 (Reuters) - Canada’s main stock index dipped on Wednesday after a six-day rally as declining gold prices dragged down miners, while the central bank held it key interest rate as expected. * At 10:27 a.m. ET (1527 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 26.79 points, or 0.15%, at 17,613.56. The index hovered near its strongest level since late February. * The Bank of Canada left its key interest rate unchanged at 0.25%, and said it would maintain its current policy of quantitative easing. The central bank reiterated it would leave rates unchanged until some point in 2023. * The Canadian dollar was trading 0.3% higher at C$1.2778 to the U.S. dollar. * Miners fell most on the index as gold prices decreased 1%, with optimism over COVID-19 vaccine developments prompting a rush for riskier assets. * SSR Mining Inc fell 4.0%, the most on the TSX, while the second biggest decliner was Silvercorp Metals Inc , down 3.7%. * The energy sector gained 1.6% on a jump in U.S. crude prices due to hopes of a recovery in fuel demand and the U.S. dollar, in which oil is traded, reached 2 1/2-year lows. * Shares in oil producer Whitecap Resources Inc jumped almost 12% to the top of TSX after it agreed to buy rival TORC Oil & Gas Ltd in an all-stock deal valued at about C$552 million ($430.81 million). Torc’s shares rose 7.3%. ** Dollarama Inc rose almost 3% after it beat analysts’ estimates for third-quarter sales. * Among other top gainers on the TSX was Vermilion Energy Inc, which rose 4.1% * The most heavily traded shares by volume were Whitecap Resources Inc, Crescent Point Energy Corp and Air Canada. * The TSX posted eight new 52-week highs and no new lows. * Across all Canadian issues there were 67 new 52-week highs and five new lows, with total volume of 72.96 million shares. * On the TSX, 109 issues were higher, while 108 issues declined for a 1.01-to-1 ratio favoring gainers, with 37.09 million shares traded. (Reporting by Sruthi Shankar in Bengaluru; Editing by Krishna Chandra Eluri)