AbitibiBowater officials could announce as early as Thursday how long they expect Fort Frances Mill will be shut down for.
Operations were halted Tuesday when staff uncovered a problem with the mill's effluent treatment system.
Company spokesman Jean Philippe Cote says it is believed cold weather is to blame for difficulties that caused them to exceed biochemical oxygen demand limits set by the Ministry of Environment.
External consultants are now working with company personnel in analyzing the problem and determining the appropriate course of action.
Cote said he is hopeful that a preliminary analysis will be available soon. But until that happens, he says there is no way to project when operations will resume.
The Fort Frances mill employs over 560 workers.