May 2 (Reuters) - Shares of Aurizon Mines Ltd fell on Thursday after authorities in Quebec said a dam had broken at its Casa Berardi mine, spilling contaminated material into James Bay.

Some 150,000 cubic meters of liquid and 15,000 cubic meters of solid material was spilled, according to a release from Quebec's Ministry of Sustainable Development, Environment, Wildlife and Parks.

Shares of Aurizon were down 6.3 percent at $3.99 when the stock was halted pending news at about 11:00 a.m. ET (1500 GMT). A spokesperson was not immediately available for comment.

Aurizon agreed in March to be taken over by U.S.-based silver producer Hecla Mining Co in a friendly deal that values Aurizon at about C$796 million ($789.41 million).

The company briefly suspended operations at Casa Berardi later that month after a contractor was killed in a vehicle accident.