Tanami Desert, Northern Territory, Australia
The Tanami mine is an underground gold mine in the Northern Territory of Australia. It is the second-largest underground gold mining operation in the country.
The mine was commissioned in 1986 and has produced more than ten million ounces (Moz) of gold to date. It is wholly owned and operated by Newmont, a major gold producer based in the US.
The mine has approximately 1,200 direct and indirect employees, who work on a fly-in, fly-out (FIFO) basis to support the extraction of resources as the mine is situated in a remote location.
Location of Tanami gold mine
The Tanami gold mine is located adjacent to the Tanami Highway in the remote Tanami Desert.
The site is situated at a distance of 563km north-west of Alice Springs and 949km south-west of Darwin.
The land on which the mine and the plant are located is owned by the Warlpiri people, a community of indigenous people. The Central Desert Aboriginal Lands Trust manages the property on behalf of the aboriginal people.
Tanami gold reserves
Tanami gold mine is estimated to contain 33.2 million tonnes (Mt) of proven and probable reserves graded at 5.31g/t as of 31 December 2019.
In February 2020, the company revised the reserves and resources estimate of the mine, adding 1.5Moz of gold reserves, 1.1Moz of measured and indicated resources, and 1.6Moz of inferred resources.
Tanami gold mine details
The Tanami operations are divided into two separate sections, the Granites section and Dead Bullock Soak (DBS). The Granites area houses the administration and processing operations along with the accommodation for the FIFO workforce, while the Dead Bullock Soak (DBS) or the Callie underground mine is dedicated to production and maintenance.
Ore is presently recovered only from the underground operation at DBS. In addition to Callie, DBS includes two more orebodies, namely Federation and Auron.
The Granites area employed open-cut and underground mining between 1988 and 2003 while DBS employed open-cut mining during the period between 1990 and 2002 with underground mining beginning in 1994. The underground mine at DBS is currently the only active mining operation at the mine site.
Long-hole open stope method is used to extract ore from the Callie underground mine. The ore is transported via underground dump trucks to the surface for stockpiling and then hauled by road trains for crushing and processing at the Granites.
Tanami mine expansion
Tanami gold mine underwent the first expansion in 2017, which included the creation of a second decline in the underground mine and additional processing capacity. It improved production and increased the mine life by three years. The final commercial production from the expansion was achieved in 2017.
The expansion involved increasing the annual capacity of the processing plant from 2.3Mt to 2.6Mt through the addition of a thickener, ball mill and gravity circuit.
The Tanami Expansion 2 project was approved in October 2019. It is estimated to extend the life of the Tanami mine beyond 2040.
The planned expansion of the Tanami operations will be mainly driven by the Auron orebody, which was discovered in 2008. The Auron deposit is present below the Callie orebody and Federation and Liberator discoveries.
The expansion will add 150,000-200,000oz per year of average gold production in the first five years, with commissioning expected in 2023. With an estimated capital investment of around $700-800m, the project will reduce operational expenses by 10%.
The project will enable the recovery of ore from 2,140m below the surface. It will involve the construction of a 1,460m shaft, along with increasing the capacity of the processing plant.
Infrastructure at Tanami mine
Newmont completed the Tanami power project, including the installation of two power stations to support the mine with a reliable source of energy, in March 2019. A 66kV interconnected power line and a natural gas pipeline were also installed.
The 8in, 450km-long Tanami natural gas pipeline supplies up to 13TJ a day of natural gas to the power stations at the mine.
The power project provides a reliable gas-fuelled power generation system by replacing the use of diesel fuel at the site.
The Tanami processing plant was commissioned in 1986 and was expanded in 2017. It includes a grinding circuit, crushing plant, tailings disposal facility and gravity carbon-in-pulp tanks.
Australian Gas Infrastructure Group (AGIG) was contracted to construct, own and operate the Tanami gas pipeline while Zenith Energy was selected to build and operate the power stations.
WorleyParsons was awarded a contract to provide engineering, procurement and construction management (EPCM) services, in February 2019. Tetra Tech Proteus conducted studies for the improvement of the mine.
Robertson GeoConsultants performed a hydrogeological review and evaluation of the tailings operations on the groundwater system in the area.
CPC Engineering provided engineering and procurement support services in support of the expansion of the Tanami mine. Newmont awarded a contract to Valmec to perform infrastructure works for the second expansion project at the mine.