The Jervois copper project is an open-pit and underground copper-silver-gold mining project planned to be developed in Northern Territory, Australia.
The Jervois project comprises three main deposits, namely Reward, Bellbird and Rockface. The project was acquired by Australian mineral explorer and developer KGL Resources in 2011.
The environmental approval for the copper mining development was recommended by the Northern Territory Environment Protection Authority (NT EPA) in October 2019, while the Northern Territory Government approved the mining management plan for the project in January 2021.
The pre-feasibility study (PFS) for the project was completed in December 2014 and an updated PFS was announced in December 2020.
With a pre-production capital investment of approximately £113m (A$200m), the Jervois project is expected to produce 222 thousand tonnes (kt) of copper along with 6.7 million ounces (Moz) of silver and 64 thousand ounces (koz) of gold by-products by treating a total of 11.3 million tonnes (Mt) of mineralised material over an initial mine life of 7.5 years.
Location and geology
The Jervois copper project area comprises the exploration license EL 25429 and four mineral licences, namely ML 30180, ML 30182, ML 30829 and ML 32277. The licences are held by Jinka Minerals, a subsidiary of KGL.
The project is located approximately 270km north-east of Alice Springs, on the south-eastern edge of the Jervois Range, within the eastern part of the Arunta Region.
A sequence of lower-to-middle amphibolite grade metasedimentary rocks of the Bonya Metamorphics, a unit in the Aileron Province of the Palaeoproterozoic eastern Arunta Region, hosts the base metal mineralisation at the Jervois mine.
The base metal mineralisation is stratabound and occurs in steeply-dipping lodes of calc-silicate, garnet-chlorite-magnetite rock and garnet-magnetite quartzite, within the andalusite-cordierite schist and quartz-sericite-magnetite schists.
Mineralisation and reserves
The massive to semi-massive sulphide copper-gold-silver mineralisation at the property is associated with quartz veins, thin interlayers in meta-mudstone, and calc-silicates.
The mine is estimated to contain JORC-compliant probable reserves of 9.4Mt grading 2.41% copper, 32.9g/t silver, and 0.39g/t gold, as of December 2020.
The resource estimate of the Jervois project stands at 20.97Mt grading 2.03% copper and 31.8g/t silver.
The conventional open-pit mining method will be applied to produce the copper-gold-silver mill feed at the Reward and Bellbird deposits, whereas the underground mining method with a decline will be used for producing the copper-silver-gold mill feed at the Reward, Bellbird and Rockface deposits.
The stage one operations of the Reward and the Bellbird open-pits will facilitate access to the Rockface decline from a small starter pit at the Bellbird open pit area for the commencement of Reward underground. The stages two, three, and four open-pit operations at Reward will be mined using a two-excavator mining fleet for two years.
The extracted ore materials will be delivered to stockpiles on the run-of-the-mine (RoM) pad and re-handled into an ore feed bin through a front-end loader, and then fed into the processing plant through the crushing circuit.
The process plant will comprise a single-stage crushing circuit along with a conventional SAG mill grinding circuit, and a smaller regrind mill. The feed will be passed through the roughing, cleaning, and re-cleaning stages in the flotation circuit.
Tailings will be thickened before being pumped to the tailings storage facility (TSF). A filter press will used to dewater the concentrate for re-use.
The plant will have of processing capacity of 1.6 million tonnes per annum (Mtpa), and will produce 30,000t of copper, 893,000 ounces (oz) of silver, and 8,600oz of gold year.
The concentrate produced at the process plant will be transported to Alice Springs by road and then to Adelaide by rail for export.
Xenith Consultants prepared the ore reserves report for the Jervois copper project while Mining Associates prepared the updated JORC report for the Reward, Rockface and the Bellbird deposits.
Balance Advisory, a logistics consultant, examined options for transporting the concentrate to various ports including Darwin, Adelaide and Townsville.
Entech undertook open-pit and underground mine optimisation, design, scheduling, as well as the geotechnical evaluation.