The Swiss mining giant acquired the project from Centennial Coal in October 2007 and inherited the mine development plans that had been approved four months earlier.
But Xstrata has since reviewed these plans and is seeking federal government approval for its modifications as required by the Environmental Protection and Biodiversity Act.
The main change is to relocate a 500-kilovolt transmission line away from the interior of the project area to the northern and western boundaries.
Xstrata is also seeking to expand the total project area.
The company said it would mine an area adjoining the approved project disturbance boundary “where the coal is now known to be close to the surface”
Mining in this new zone will disturb an extra 8.4 hectares.
Xstrata will also need an extra 1.6ha for the drainage works for the approved rail loop plus another 1.7ha for the raw water dam to reach full inundation.
Relocating the existing transmission line is expected to take 15 months and is expected to start in the December quarter once government approval is received.
The near-surface coal in the newly discovered area is expected to be mined in 2012-15.
The mine is anticipated to produce 10.5 million tonnes of run-of-production at full operation.
The project was considered 30% complete in Xstrata’s half-year report last week with the coal-handling and processing plant expected to be ready in the first half of 2011.
Prestrip mining is due to start this September, while the mine was previously scheduled to kick off production in 2012.
The mine will produce thermal coal for export and domestic markets for a mine life of at least 18 years.