Wambo mine manager Bill Dean told ABC News the approved changes would make underground and opencut operations more efficient, allowing the maximum amount of coal to be recovered.
"This is a modification to the previous development consent granted in early 2004; it provides for access from the current opencut highwall to a block of approximately 26 million tonne of high quality coal and it is planned to mine the area by longwall methods over a period of some 10 years," he said.
Wambo's current opencut operation produces 4.2Mt ROM coal per annum and holds resources of 690Mt.
Expansion plans include extension of the opencut to produce 7.5Mtpa ROM and extension of the Wollemi drift to provide access to lower, unmined seams.
