Millar Western says it is closing its Boyle lumber mill in northern Alberta indefinitely.
The Edmonton-based company says softwood market conditions make it uneconomical to continue operating.
The plant is to begin a phased shutdown starting next month be completed in February.
Millar Western says the 91 workers who are to lose their jobs will be offered severance and other support.
The family-owned company says its Whitecourt and Fox Creek operations will continue to operate at full capacity.
Boyle is a village about 160 kilometres north of Edmonton.