Telford Cut was a coal mine in South Australia and terminus of the Stirling North to Marree line. As of 19 November 2015, its remaining product was used by the Northern Power Station, Port Augusta, until it too closed in May 2016.
The open cut mine operation was for low-grade, sub-bituminous black coal which is frequently referred to as hard brown coal or just brown coal. It is transported 250 km by rail to power stations outside Port Augusta on the east side of Spencer Gulf. The coal occurs in several nested bowl-shaped seams, each several metres thick. The coalfield at Leigh Creek was operated by the Alinta Energy and currently produces over 2.5 million tonnes a year of coal. Alinta energy also operates the power stations at Port Augusta which are the only remaining coal-fired generators in South Australia, and the only users of coal from Leigh Creek.
In 1888, John Henry Reid discovered coal-bearing shale during the sinking of a railway dam in the Leigh Creek area (Henry Brown, Government Geologist confirmed the find in his visit to Leigh's Creek in February 1889). This discovery led to a geological examination of the area by a government geologist and the establishment of underground workings. No 1 shaft, sunk by the Leigh Creek Coal Mining Company, was abandoned on striking a heavy flow of water. A new shaft was sunk in 1892 but only small quantities of coal were extracted for experimental purposes and operations ceased in 1894.
It was not until 1940 when coal supplies became critically low because of the Second World War that Leigh Creek coal was considered again. The deposits seemed extensive and extracting the coal by open cut methods was considered feasible. Exploratory boring started in 1941 and plans were made to develop the first open cut mine. Excavation started in 1943 under the control of the Engineering & Water Supply Department. It was apparent that the electricity supply industry would be the largest user of Leigh Creek coal so control of the coalfield was transferred to the Electricity Trust of South Australia (ETSA) in 1948.
ETSA ordered boilers capable of burning Leigh Creek coal for the Osborne Power Station near Port Adelaide and, after thorough investigations, decided to establish a power station at Port Augusta to burn Leigh Creek coal exclusively. The combined A and B plants, with a total generating capacity of 330 megawatts, was named the Thomas Playford Station in recognition of the then South Australian Premier, Sir Thomas Playford.
The use of large excavating machines and efficient mining equipment at Leigh Creek, together with the rebuilding of a railway line between Leigh Creek and Port Augusta by the Commonwealth Railways, resulted in economic production and delivery of coal to the power station. Pacific National provided the coal freight service from 2001.
In the mid 1970s it was decided to build a 500 megawatt station at Port Augusta, called the Northern Power Station. That decision meant enlarging the coalfield using new methods to extract deeper coal, increasing production, building a retention dam to prevent possible flooding of the field and diverting the main highway around the coalfield. The Northern Power Station, alongside Playford A and B, was commissioned in 1985. Because the existing town was located within the coal basin, a new town was built south of the coalfield and the new Leigh Creek became occupied in 1980.
Since the early 1990s, more changes occurred in Leigh Creek. Massive restructuring of mining operations resulted in the reduction of a workforce of over 750 to about 200. The township also became a lot smaller. The population dropped from about 2500 in 1987 to less than 700 today. The loss of residents also resulted in the loss of many services. Whilst most workers at the coalfields make a good income, the high cost of communication and services drastically reduce the disposable income. Schooling at Leigh Creek has become a bigger problem than ever before. Reasonable education is available for younger students in the primary school. For high school students, the meagre subject choice has made education at the Leigh Creek Area School not the ideal option for many students. Many parents have to send their children away at 13 years old, to get a good education in Adelaide or regional cities like Port Augusta. A simple medical procedure may require a trip to Adelaide, which means a round trip of about 1200 km.
On 11 June 2015, Alinta Energy announced their intent to not operate the Leigh Creek coal mine beyond March 2018, closing it along with the related Playford B and Northern power stations. All of which may close sooner should business conditions worsen further.
On 30 July 2015, Alinta Energy announced they were bringing the closure dates of all three facilities forward by 12 months, and now intended to no longer operate them past March 2017 and could shut them down as early as March 2016. The closure date for the Port Augusta power stations was later delayed until 8 May 2016.
On 7 October 2015, it was confirmed that the Leigh Creek mining operations would cease on 17 November 2015.
The nearby town of Leigh Creek supported the mine during its operation.
Coal was originally transported by a 1,067 mm (3 ft 6 in) gauge railway that went needlessly in and out of the Flinders Ranges via Hawker (315m amsl) and Quorn (293m amsl). This was eventually replaced by the more efficient 1,435 mm (4 ft 8 1⁄2 in) Marree line that stayed on the flat side of those ranges.
The railway now finishes in a balloon loop. The standard gauge railway used to continue to Marree until 1980, while the narrow gauge railway used to continue to Alice Springs.