Xstrata has applied to the NSW Department of Planning to extend the lifespan and workforce of its Ravensworth coal mine.
Dubbed the "Underground Mine Modification 9", it is part of the miner's gradual development of the Liddell Seam.
According to the miner its objective with the application is to "develop the ongoing underground operations" which will see it change the width, orientation, and location of longwall panels.
While it will reduce the number of panels from 19 down to 18, the width of each longwall panel will increase by around 35 metres.
This latest application from Xstrata seeks to modify the existing approved mine plan as well as "install additional surface infrastructure to ensure adequate gas drainage and ventilation", the miner says.
This infrastructure includes new pit top facilities; conveyors; tailings pipelines; a substation; RCHPP and RCT; and fuel storage facilities, as well as new fire ventilation shafts and goaf drainage wells.
While this will see additional methane gas vented in the early stages levels are predicted to drop soon after, and then stabilise.
As part of this growth it will also expand its workforce from just over 300 employees to a long term average of more than 400, with the occasional peak driving staff numbers above 500.
This latest development of its Hunter Valley underground coal mine comes only weeks after it announced plans to re-open its closed Blakefield South coal mine, after it was forced to shut the operation down due to underground fires.