Tahmoor South Project, New South Wales, Australia

The Tahmoor South Project is a proposed expansion of the Tahmoor Mine located in New South Wales, Australia. The existing mining operation at the Tahmoor mine’s north lease area is due to cease in 2022 while the Tahmoor South Project will extend the life of the mine by a further ten years until 2032.

Tahmoor Coal, a wholly-owned subsidiary of Simec Mining, is the operator of the Tahmoor mine since 1979. Environmental and planning studies for the Tahmoor South Project began in 2011 while a preliminary environmental assessment (PEA) was completed in September 2012. Completed in late 2014, the environmental impact statement (EIS) for the project was not submitted to the planning authorities as the project was briefly halted due to unfavourable coal market conditions.

A comprehensive EIS was prepared in June 2018. The Independent Planning Commission of New South Wales granted the development consent for the project in April 2021.

The Tahmoor South Project will secure the employment of more than 400 workers at the existing NSW coal operation until 2032 while generating more than 170 new jobs during the proposed two-year construction period.

Tahmoor South Project location and geology

The Tahmoor South Project extension of the Tahmoor coal mine is located immediately south of the current mining operations. The Tahmoor coking coal mine is an existing operation located in the Southern Coalfields, approximately 80km south-west of Sydney, within the Wollondilly Shire Council.

The primary target is the Bulli Seam while the Lower Wongawilli Seam is the second target, located 25m below the Bulli Seam. The target Bulli and Wongawilli seams are hosted in the Permian Illawarra Coal Measures, overlain by the Triassic Narrabeen Group comprising interbedded sandstone and claystone units, the Wianamatta Group that contains shales and siltstones and Hawkesbury Sandstone Group.

The Bald Hill Claystone, which is located approximately 200m above the Bulli Seam, is included in the Narrabeen Group and the thicknesses of the formations are relatively consistent across the Tahmoor South mining area.

Tahmoor South Project mineralisation and reserves

The Bulli seam, which is the main target of the Tahmoor South Project, is located approximately 375m to 430m below the surface with a thickness of 1.8m to 3.3m.

The measured, indicated and inferred mineral resources within the project area are estimated at 20 million tonnes (Mt), 243Mt and 114Mt, respectively.

Mining at Tahmoor South Project

The proposed development will involve mining coal from the Bulli Seam within the central domain using underground methods of longwall mining. Mining operations are planned to be undertaken via the main roadway and longwall development. The Tahmoor South Project is expected to extract up to 4Mt of a run of mine (ROM) coal a year, with up to 33Mt of ROM coal proposed over the life of the project.

A total of 12 new longwall panels with a width of approximately 305m will be developed while the gate roads would be approximately 5.2m wide with a height of up to 3m. Ore is proposed to be cut from the coal face by a longwall shearer and loaded onto the armoured face conveyor for transportation to the existing surface infrastructure via underground conveyors.

The longwall will retreat over the course of mining operations, causing the overlying rock strata to collapse to form the goaf. The proposed development is expected to use the existing infrastructure at Tahmoor Mine for employee and material access to the mine.

The existing surface facilities area of the Tahmoor Mine will be used to access the central domain via the T3 vertical lift, which has a capacity for 70 persons and approximately 12t of materials.

Processing details

The ore mined from the Tahmoor South Project will be processed at the existing Tahmoor coal handling and preparation plant (CHPP), which has a processing capacity of 650t/h. The coal handling plant will separate coal into the high-quality coking blend as the primary product and low-quality steaming blend as the secondary product while removing rock and other foreign materials through screening and cyclonic processes.

The processed coal comprising 90% to 95% metallurgical or coking coal and 5% to 10% thermal coal will be transported via the existing Main Southern Railway and the Moss Vale to Unanderra Railway on to the port of Kembla for domestic market and export to overseas markets.

Contractors involved

The EIS for the project was prepared by the integrated technical and management support services company AECOM Australia.