Oct 27 (Reuters) - Canada's main stock index inched slightly lower at the open on Tuesday, weighed by weakness in the materials sector and dismal earnings from Teck Resources Ltd .

* At 9:31 a.m. ET (1331 GMT), the Toronto Stock Exchange's S&P/TSX composite index was down 9.47 points, or 0.06%, at 16,070.08. (Reporting by Amal S in Bengaluru, Editing by Ramakrishnan M.)