March 8 (Reuters) - Canada’s main stock index opened flat on Monday, as gains in energy stocks were somewhat offset by mining stocks which tracked weaker bullion prices. * At 9:30 a.m. ET (14:30 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 2.09 points, or 0.01%, at 18,383.05. (Reporting by Amal S in Bengaluru)