Mill operations have been suspended since November and White Birch had said it would close permanently unless the company significantly lowered salary, pension benefits and other costs.
The Communications, Energy and Paperworkers Union says the rejected offer included a demand that the workers accept a 21 per cent pay cut.
But union vice-president Renaud Gagne says it was the pension proposals that caused the most dissatisfaction.
He says workers aged over 55 would have 45 per cent of the value of their pension and younger employees would lose 65 per cent.
Gagne says the union seek a special intervention Thursday through the Ministry of Labour to bring the employer back to the bargaining table.
Greenwich, Conn.-based White Birch was the second-largest newsprint manufacturer in North America when it filed for bankruptcy protection in February 2010.
At the time it had about 1,300 employees at three pulp and paper mills and a saw mill in Quebec and a fourth pulp and paper mill in Virginia.
The company manufactures high quality newsprint, directory paper and paperboard at mills in Canada and the United States.
But a switch to digital publications has eroded demand for paper used in newspapers and directories.
Rising energy prices, a strong Canadian dollar and low returns for company pensions have also raised costs for the industry.Suggest a correction