As a result, a special committee of directors has been considering strategic alternatives since September, including a possible sale of the company.
"At the present time there is no certainty that any financing or sale of one or more of the company's projects, or the company itself, will be completed," High River said.
Directors Graham Farquharson and Bob Buchan, who joined the board in September when the special committee was formed, have resigned.
The company said Farquharson was leaving for personal reasons but didn't give an explanation for the departure of Buchan, a mining industry veteran who founded Kinross Gold Corp.
With files from the Canadian Press