The industrial action will continue the push for better pay and conditions under a new collective agreement at the Hunter Valley mine.

Workers began industrial action last week with a total of 48 hours of stoppages, but since an agreement has not been reached, the action is stepping up.

Construction, Forestry, Mining and Energy Union (CFMEU) spokesperson Graham Kelly said workers were not satisfied with the 4% up front pay increase proposed by Xstrata when negotiations first began.

“From our point of view, Xstrata mine workers and the employees at United are pretty disappointed with the company’s offer, we’ve been negotiating this agreement since September and we would have expected more from a company which, at this particular mine last year, made $107 million,” he said.

He said if the union received their claim from Xstrata, it would cost the company just $1.5 million extra per annum.

Kelly said the union had already worked through a number of problems with Xstrata and had compromised to achieve the needs of the business and the needs of union members.

“Our intention now is to show them the workers don’t believe its good enough and we want them to listen to the complaints. They’ve made no effort to change their offer since the day they put it on the table,” he said.

"We are open to negotiations between now and Thursday, and we'll make ourselves available if Xstrata want to progress the outstanding matters."