Limited coal extraction has been conducted from the Fassifern Seam where it is exposed around the hillside of the Tasman deposit.

The 30m to 110m thick Tomago Measures include the previously mined Great Northern Seam which lies from 7m to 30m above the proposed workings and by the West Borehole Seam that lies approximately 150m beneath the Fassifern Seam.

The overburden typically comprises several conglomerate units with interbedded siltstone, claystone and sandstone overlying the Great Northern Seam, the Awaba Tuff and Fassifern Seam and dip at <5° towards the south-east.

Mining commenced at Tasman Mine in late 2006. The current method of mining is bord and pillar using continuous miner-bolters and shuttle cars for first workings and secondary extraction using breaker line supports. The two stage process was chosen to accommodate irregular shaped coal deposits, allowing adjustments to be made to extraction ratios for better management of subsidence and to maximise the efficiency of the operation.

Tasman Mine employs the Duncan method of partial pillar extraction. The mine commenced pillar extraction employing a full-extraction modified Wongawilli system in March 2008. After completion of the first panel a system of secondary extraction was deemed more suitable for the poor caving conditions.

Donaldson Open Cut Coal Mine ceased in March 2013. This mine represented only 1.6% of Yancoal’s total energy consumption.

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