July 20 (Reuters) - Canada’s main stock index opened flat on Tuesday as losses in energy stocks on weaker crude prices offset gains in miners. * At 9:34 a.m. ET (13:34 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was up 3.82 points, or 0.02%, at 19,730.27. Reporting by Amal S in Bengaluru; Editing by Aditya Soni Our Standards: The Thomson Reuters Trust Principles.