The geology at WCC (Werris Creek Coal) Mine as located within the Werrie Basin is containing Permian sedimentary and volcanic rocks that unconformably overlie the Middle Cambrian to earliest Permian basement of the Tamworth Belt, Southern New England Orogen. The geology at WCC is an outlier of the Early Permian Willow Tree Formation, which is now recognised as equivalent to the Greta Coal Measures, which unconformably overlies the Werrie Basalt.

Two lithostratigraphic units occur within the equivalent Greta Coal Measures (Skeletar Formation and Rowan Formation) and one lithostratigraphic unit from the Maitland Group (Railway View Conglomerate) are recognised in the Werris Creek outlier. The equivalent Greta Coal Measures contains at least nine coal seams, with the formal names of coal members chosen to correspond with the earlier alphabetical seam identification. The coal seams range in depth from as little as 10m at subcrop to an estimated 180m in the centre of the basin. Weathering depths range from 10 – 50m. Individual seam thicknesses are up to 8m but are more commonly in the range 3 - 4m. Underlying the coal measures is the Werrie Basalt, a sequence of deeply weathered basaltic lavas, volcanoclastics and palaeosols.

The Werris Creek coal deposit is contained within a closed syncline whose longitudinal axis is oriented NNW-SSE. Dips near subcrop are up to 60o , but flatten towards the centre of the basin. The irregular upper surface of the Werrie Basalt may have affected deposition of the overlying coal measures. A basement high is thought to be responsible for the thinning of G Coal in places, and up to 40m relief is inferred. A number of small faults with displacements of up to 2m were recorded in the old underground workings. A complex NNW- trending graben structure traverses the open cut mine, with displacements of up to 5m. Faults are also inferred from boreholes. Dykes were also recorded in the old mine, in the open cut and in boreholes.

The coals at Werris Creek are bituminous, high volatility (VM+/-35% daf), low sulphur (<0.35%) and vitrinite-poor. The coals are non-swelling to very weakly caking. Ash content is generally low to medium.

Mining will continue to be undertaken utilising the same conventional haulback mining methods that are currently implemented at the mine. This method involves the following activities which will generally be undertaken in the following sequence.
1. Vegetation removal.
2. Drainage installation.
3. Soil stripping.
4. Blasting, excavating and overburden emplacement dumping.
5. Coal recovery.

Mining occurs at the lowest elevations within the open cut. The number of haul trucks will progressively reduce over the life of the Mine as the mining progresses up dip of the synclinal coal seams. Should there be any significant change to the number or use of equipment on the Mine, the change will be documented through the AEMR process.

In order to offset the higher overburden / interburden to coal strip ratios encountered at the Mine, the development of a north-south oriented bench targeting the shallow, low strip ratio coal along the western edge of the mining area is proposed.

As the open cut moves through the base of the synclinal coal measures, the north-south oriented bench and would merge with the east- west oriented benches creating an approximately 45° angled bench.

As the open cut progresses towards the northern perimeter, with all coal seams occurring closer to surface as the syncline dips up, the benches would again revert to an east-west orientation to allow for multiple coal seams to be mined concurrently, thereby keeping the coal quality and strip ratio consistent.

Located predominantly within and above the void created by the open cut, the 400m to 445m AHD section of the Overburden Emplacement will be extended by approximately 250m to the north to provide for an increased capacity of approximately 13.5Mbcm.

In line with current overburden design principles, the low wall of the advancing northern face of the in-pit emplacement will be constructed with slopes of 18º (1V:3H) or less. On the out-ofpit eastern and western slopes, the slopes of the overburden emplacement will be constructed with comparatively gentle slope of approximately 10°. On the outer slopes and final in-pit (northern) slope, existing contour banks will be extended to manage surface water runoff and assist in minimising erosion of these slopes.

While the volume of overburden/interburden requiring placement within the overburden emplacement is greater than previously predicted, there will be no change to the current method of haulage, placement and profiling of overburden and interburden.

Coal is segregated at the ROM coal stockpile based on the expected ash content of the coal. The higher ash coal products are processed through the fixed plant crusher and subsequently processed through the secondary crusher. Low ash coal products are processed by the mobile crushers and then screened.

No washing of the coal is undertaken or proposed, however, dry separation of higher ash or impurity coal will reduce the ash content of the coal to meet export coal requirements.

Product coal is transported by road trucks from the coal processing area to the product coal stockpile area at the train load out facility via the private coal haul road. The despatch of product coal from WCC is either railed to the Port of Newcastle or transported by road to domestic customers.

The mine produces both thermal and PCI coal with low to medium ash, low sulphur, low phosphorous and medium to high volatility.