Oct 29 (Reuters) - Canada’s main stock index retreated on Friday, as miners lost their footing on weaker bullion prices, while technology stocks tracked weakness in the U.S. tech-heavy Nasdaq. At 9:33 a.m. ET (1333 GMT), the Toronto Stock Exchange’s S&P/TSX composite index was down 105.62 points, or 0.5%, at 21,091.91. (Reporting by Amal S in Bengaluru; Editing by Maju Samuel)