May 15 (Reuters) - Canada's main stock index opened slightly higher on Monday aided by gains in materials and energy stocks, but shares of Northern Dynasty Minerals Ltd fell, logging the company's worst day in over a week on going concern worries.
At 9:34 a.m. ET (1334 GMT), the Toronto Stock Exchange's S&P/TSX composite index was up 22.98 points, or 0.11%, at 20,442.6.
(Reporting by Johann M Cherian in Bengaluru; Editing by Pooja Desai)
