Dawson Complex, Queensland, Australia – Mining Technology


The Dawson Complex is located 185 km southwest of Gladstone Harbor, Queensland, Australia. It integrates several previous coal mining operations in the region, including the Moura mine.

Coal has been mined at Moura since 1961, making it one of the oldest operations in central Queensland. Moura is also home to Australia’s first commercial coal bed methane recovery operation.

Originally operated by BHP Mitsui Coal, the mine changed hands in mid-1999 when Peabody bought a 55% stake in BHP.

Since 2001, ownership changed again, first to Rio Tinto’s subsidiary, Coal and Allied, after which Mitsui invoked his pre-emptive rights to purchase the entire operation before selling a 51% stake. at Anglo American in mid-2002.

An $ 839 million expansion project was completed in 2008 at the mine. The project included three separately identifiable mining areas sharing a common infrastructure: Dawson North, Dawson Central and Dawson South.

Surface and underground mining took place, as well as a high-wall mining system.

In 2019, the Dawson mine produced 3.9 Mt of metallurgical coal. Approximately 1,300 employees and contractors are currently employed at the mine.

The coal mine is expected to have sufficient resources to ensure a remaining life of approximately 18 years.

The mining expansion plans include a proposal to extend the existing surface mining areas.

Geology and reserves of the Moura mine

Moura is found in the Baralaba Coal Measures on the southeast flank of the Bowen Basin. The mine produces coal from Permian age reserves contained in five main veins with an average thickness of 3.5 m to 4.0 m and a dip of 5 ° to 12 °.

As of December 2019, the Dawson complex had total proven and probable ore reserves of 173.6 Mt, total measured and indicated resources of 757.1 Mt and inferred resources of 455.8 Mt.

Extraction methods

After blasting, the primary stripping of the open-cast waste is carried out by four draglines: a Marion 7901 equipped with a 30 m³ skip, a Bucyrus-Erie (BE) of 47 m³ and two Marion 8200 equipped with 57 m³ skips and 72 m³.

The main coal loading equipment is a fleet of six Cat 992C wheel loaders, equipped with 20 t capacity buckets that operate with seven 135 t Cat 776 dump trucks and one 160 t Cat 776C machine. .

High wall mining

The Moura high-wall mining system was commissioned in mid-1997, BHP estimated that in 2012 there would be 127 Mt of high-wall reserves at the mine. Since more than 80% is retained in veins with an inclination greater than 6 °, conventional high-wall mining equipment cannot perform satisfactorily.

Mining Technologies Addcar’s original high-wall mining system was replaced by a remote controlled Joy 12CM12B continuous miner. A system using the Archveyor concept developed by Arch Coal was then deployed. There are now two units in operation in Moura.

Coal preparation and transport

Raw coal from surface mining and high-wall mining is transported 16 km by an overland conveyor belt to the preparation plant area. Here, the crushing in three 2,000 tph rotary mills is followed by the transfer of the crushed coal to the preparation plant itself, where a washing system with several circuits (dense medium, spirals and flotation) is used to give coarse, medium and fine coal products.

The washed coal is transported by rail to Gladstone and shipped via the coal terminals at Barney Point (owned by BHP Mitsui Coal) and RG Tanna.

Coal production and resources at the Dawson complex

Dawson is a brownfield expansion aimed at increasing production to 12.7 Mtpa of salable coal for the marine market to meet the growing demand for high quality metallurgical and thermal coals. The coal seams will be mined along a longitudinal length extending 10 km north of the existing mine rail dump and 60 km south.

Dawson North has an identified coal resource of 34 Mt, with a potential of an additional 20 Mt and will produce 2.1 Mtpa of high quality marketable metallurgical coal. Dawson Central, which encompasses the existing operation, contains an identified resource of 158 Mtpa of coal, with a potential of an additional 95 Mt and will produce 5.0 Mtpa of salable metallurgical coal and 2.7 Mtpa of salable thermal coal.

Dawson South contains an identified resource of 89 Mt of coal with a potential of an additional 10 Mt and will produce 2.9 Mtpa of marketable high energy thermal coal.

Coal quality

Coking coal quality parameters for Moura KCOAL:

  • Total humidity: 10.5%
  • Volatile matter: 32.0%
  • Ash: 8.3%
  • Sulfur: 0.42%
  • Crucible swelling index: 6

Quality parameters for Moura thermal coal:

  • Total humidity: 10.5%
  • Volatile matter: 30.5%
  • Ash: 10.0%
  • Sulfur: 0.50%
  • Calorific value: 30.35 MJ / kg (13,050 BTU / lb)

Entrepreneurs

Leighton Contractors was hired to perform surface mining in the Dawson North area. Leighton was awarded a two-year contract worth $ 159 million in November 2010. A $ 120 million extension contract was also awarded in December 2011.

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