About 20 unionized workers from the Xstrata Zinc Brunswick Mine held an information picket in Bathurst to protest significant reductions in their pensions.

The mine is in the process of closing down this spring and one group of employees are finding the pensions they are being offered do not match what the ones they were promised.

Mike Willett, the acting president of the mine’s union, said employees were given a pension statement last July, which explained options like retiring or taking a severance package and opting out of the pension program.

But, he said, the pension calculations changed between July and January and that has caused workers to scramble.

"Almost six and a half months after the statements came out, when the first two people took their severance pay they got their money and there was over $100,000 missing under commuted value."

Willett said about 45 employees are affected by these sudden pension changes. The union leader said the missing pension money is causing a lot of uncertainty for these workers.

"Basically everybody made plans, everybody planning their future since July around these numbers and around these numbers and around these facts and basically it put a real turmoil in everybody's plans and everybody's decision and everybody's confidence also," Willett said.

The company admits there were changes made between the two pension statements.

Greg Ashe, the general manager of Brunswick Mine, said there were some information missing when the first pension statements were issued. So those employees will be given new estimates, he said.

"We're also giving them the option of — we're going to pay them until the end of March just as if — even though they've left so that they'd be leaving with the rest of our employees," Ashe said.

Ashe announced last year the mine would close in 2013. At the time, he said the closure had nothing to do with market pressures, but there was nothing left to mine.

About 2.9 million tonnes of ore were left at Brunswick Mine in March 2012 and the company can process about three million tonnes a year.

Swiss-headquartered Xstrata PLC took over the underground mine, 20 kilometres southwest of Bathurst, in 2006 with its acquisition of Falconbridge Ltd.

The mine, which is close to 50 years old, had been expected to close in 2010, but its life was extended. It has produced more than 134 million tonnes of ore since it opened in 1964.