Airly is located within the southern part of the Western Coalfield of NSW, on the western edge of the Sydney Basin. The area is underlain by Triassic sandstone of the Narrabean Group, which is underlain by the Illawarra Coal Measures. The Lithgow Seam within the lower Illawarra Coal Measures, which has an average thickness of 3.4 m, is the target coal seam at Airly Mine.

Thermal coal is mined at Airly for the export market and is extracted from the Lithgow Coal within the Illawarra Coal Measures using bord and pillar mining methods. The operation uses a continuous miner system to extract coal from underground. Full production capacity is 1.8 Mt/year.

Mine Design and Mining Operations.
During the MOP term, Airly’s underground mining operations will use a combination of first workings and partial extraction methods within ML 1331 (Mining Lease) and extend into the eastern portion of AUTH 232 (Authorisation). A Mining Lease Application (MLA) will be completed during the MOP (Mining Operations Plan) term prior to commencing activities outside of ML1331.

The Airly mine design has taken into consideration the many sensitive features within the MOP areas including cliffs, pagodas, groundwater resources and Aboriginal and European heritage sites and infrastructure. Mining methods will vary based on differing levels of environmental sensitivity and depth of cover and will be undertaken in accordance with approved Extraction Plans, which will be undertaken in a conservative staged approach consistent with development consent SSD_5581 (State Significant Development).

The underground mining area has been divided into mining zones in which different mining methods will be used to ensure the desired subsidence levels are met. Significant surface features will be protected through the use of first workings only with long term stable pillars.

In summary the following mining methods will be used in the various mining zones as defined by development consent SSD_5581 (unless amended by an approved Extraction Plan):

- Panel and Pillar Zone: This is the plateau area where depth of cover is greater than 160 m. The maximum void width will be 61 m and highly sub-critical. Long term stable pillars will be left between the voids to allow spanning of the overburden between pillars, thus greatly limiting the level of subsidence. This mining method will be used over the majority of the mining area.

- Cliff Line Zone: This is an area of first workings only (no secondary extraction at any time) defined by a setback of 30 m from both the crest and toe of the cliffs. The Cliff Line Zone includes a 26.5 degree angle of draw setback from proposed panel and pillar second workings to cliffs. An additional 50m buffer will be included in the mine design submitted with relevant Extraction Plans, which effectively establishes a combined setback of 26.5 degrees angle of draw plus 50m.

- Partial Pillar Lifting Zone: This zone extends from the Cliff Line Zone down to the 80 m depth of cover contour and is the zone of partial pillar stripping, creating limited spans (15.5m to 25.5 m) and leaving long term stable pillars remaining to provide overburden support.

- Shallow Zone: This is a second zone of partial extraction using splitting quartering of larger first workings pillars to a smaller size but remaining long term stable. The zone extends between the 20 m and 110 m depth of cover contours. Splitting and quartering is to be only carried out in areas where the depth exceeds 30m. In areas of European heritage the horizontal extent of protection areas of first workings around the heritage sites is defined by half the depth.

- New Hartley Shale Mine Protection Interaction Zone: This is an area of panel and pillar mining in the Mount Airly plateau area below the old oil shale workings. Interaction between the underlying panel and pillar mining in the Lithgow seam and the overlying oil shale workings is expected.

Materials Handling and Processing.

The Airly site does not contain a coal washery.

On-site facilities include a coal handling and preparation plant (CHPP), as well as a rail loop.

ROM coal is conveyed from the underground via the trunk conveyor. ROM coal is fed directly onto a surface conveyor system and transferred to the coal crushing and screening plant where it is sized to less than 50 mm. Crushed coal is stockpiled on the Product Coal Stockpile via the skyline tripper conveyor.

All coal is then transported from Airly Mine by rail. Coal from the Product Coal Stockpile is reclaimed via a reclaim tunnel onto a conveyor, which transfers coal to the rail bin. Coal is loaded from the bin into trains for transport offsite to domestic and overseas markets.