Production and maintenance employees at the mine – which has a total workforce of 170 – would be given until the end of this week to accept voluntary redundancies before forced redundancies were made, Construction Forestry Mining and Energy Union district president Andy Honeysett told ILN.

The block in which longwall 32 would be located is also under a swamp near Lithgow, which would be under risk if the longwall went ahead, according to local environmental protestors.

“They [Xstrata] had the opportunity to proceed to longwall 32 but they thought it is not economically viable,” Honeysett said.

“A small swamp – that was actually was created by the mine – could have gone under if longwall mining went ahead.”

The mine in the Western coalfields produces about 2 million tonnes of saleable thermal coal from the Lithgow coal seam.

Honeysett said the union would be encouraging Xstrata to let another operator mine the lease – which has about 20 million tonnes of reserve – because longwall mining was the only acceptable option for Xstrata.

With three longwall panels left, Xstrata expects to mine out remnant areas of Baal Bone for a further 2-3 years before it starts rehabilitation activities leading up to a final mine closure in about 10 years, according to its environmental assessment to the NSW Department of Planning earlier this year.

Longwall panels 29 to 31 are expected to be finished by the end of 2011.

Longwall 29 was initially designed to be 250m wide, but the total void width was scaled back to 220m as an extra subsidence precaution, while the void width of Longwall 30 is 226m and Longwall 31 is 220m.

In its EA Xstrata said it would target remnant areas for partial extraction over the next 2-3 years using continuous miners.

“These predominantly include barrier pillars within the existing workings of longwalls 1 to 28, which were not extracted as part of the original longwall mining campaign,” Xstrata said in its environmental assessment.

But the company said it would release an extraction plan detailing the methods used for the remnant areas closer to when this mining will start.

With the remnant mining period expected to end by 2013-14, rehabilitation activities are anticipated to take another 18-24 months.

Maintenance and monitoring will follow for a period of five years.

While the final land use plans are still being reviewed through a stakeholder engagement process, from a workshop Xstrata found the preferred outcome generally included a combination of grazing and bushland/wildlife habitat, “with the option of retaining some areas for future mining-related purposes where applicable”