Sept 3 (Reuters) - Canada's main stock index opened

lower on Tuesday amid broad-based losses led by mining and

energy shares, while investors awaited the Bank of Canada's

monetary policy decision due on Wednesday.

At 9:31 a.m. ET (13:31 GMT), the Toronto Stock Exchange's

S&P/TSX composite index was down 154.04 points, or

0.66%, at 23,192.14.