Tahmoor Mine lies in the southern part of the Permo-Triassic Sydney Basin, within which the main coal bearing sequence is the Illawarra Coal Measures.

Coal is mined from within the Bulli seam. The Bulli seam coal is predominantly a hard-coking coal.

Coal is extracted at Tahmoor Coking Coal by a longwall shearer and conveyed to the surface by a series of conveyors.

The area immediately in front of the coal face is supported by a series of hydraulic roof supports, which temporarily hold up the roof strata and provides a working space for the shearing machinery and the face conveyor. After each slice of coal is removed, the hydraulic roof supports, the face conveyor and the shearing machinery is moved forward.

Mining activities during the reporting period (2019) have been conducted in accordance with the approved Mining Operation Plan (MOP) and Extraction Plan approvals. Extraction of Longwall 32 was completed on 22 September 2019. Longwall West 1 extraction commenced on the 17 November 2019.

Longwall West 1 has commenced mining and three (3) longwalls are proposed within the Western Domain:
- Longwall West 1, actual start 17/11/2019 - proposed completion 20/8/2020;
- Longwall West 2, proposed start 19/05/2020 - proposed completion 28/4/2021;
- Longwall West 3, proposed start 10/6/2021 - proposed completion 21/12/2021;
- Longwall West 4, proposed start 31/1/2022 - proposed completion 9/6/2022.

Crushing and Screening: The Run of Mine (ROM) feed is normally in the size range of 0 to 250mm. The feed is sized to 100 mm using a divergator. The +100mm reports to the primary crusher and is crushed to 100mm top size. The combined product reports to the raw coal sizing screen and material over 50mm is crushed in the secondary crusher to 50mm maximum. The product from this operation is de-slimed over 2 de-sliming screens to 0.5mm.

Tahmoor Coal processes Run of Mine (ROM) Coal at an on-site Coal Handling and Preparation Plant (CHPP). The Coal Handling and Preparation Plant utilises crushing and screening, primary and secondary cyclones, and a flotation circuit to produce coking and thermal coal product which is stockpiled, before being loaded and transported by rail to Port Kembla Coal Terminal.

The CHPP is able to process 650 tonnes per hour.

Tahmoor’s Coal Preparation Plant is made up of three main sections:
a) Crushing and Screening: The Run of Mine (ROM) feed is normally in the size range of 0 to 250mm. The feed is sized to 100 mm using a divergator. The +100mm reports to the primary crusher and is crushed to 100mm top size. The combined product reports to the raw coal sizing screen and material over 50mm is crushed in the secondary crusher to 50mm maximum. The product from this operation is de-slimed over 2 de-sliming screens to 0.5mm.

b) Primary and secondary cyclones ........