As part of the process toward the mine's closure, development activities will cease at the end of next month following the establishment of the final longwall panel.

"Completion of these development activities will result in the reduction of approximately 50 full-time roles," the company said.

"Production at the mine will continue until the final volumes of coal have been extracted from the remaining longwall panels."

"We have begun consulting with employees and their representatives with respect to the proposed changes and will continue to provide information at each step of the process."

The mine's workforce of 196 now faces an uncertain future, with Glencore downsizing employee numbers at its operations since 2012.

It retrenched 450 workers last year when it restructured its Newlands and Oaky Creek operations.

Development at Newlands began in 1981, coal mining started in 1983. Coal is mined from a single seam, the Upper Newlands, which averages 6m in thickness.

The operation originally aimed to produce 4 million tonnes of washed coal per year from approximately 4.5Mt open cut coal mined.

With the start of underground mining in 1998 and significant restructuring of the open cut, the combined open cut have produced in excess of 10Mtpa.