Name of the Mine
Northparkes mine.

Location  
Central west New South Wales, Australia.

Mine Owner/s  
CMOC operates the mine on behalf of the Northparkes Joint Venture (JV), an unincorporated JV between CMOC (80%), SC Mineral Resources (6.7%) and Sumitomo Metal Mining Oceania Pty Limited (13.3%).

Brief Description  
Northparkes was the first mine in Australia to use block cave mining, now used in several mines throughout the country.

The operation comprises an underground block cave mine, a sublevel cave and an ore processing plant that produces copper concentrate for export.

Mining production is currently sourced from the E48 block cave that is nearing completion, the E26 lift 1 block cave and the E26 sublevel cave supplemented by stockpile ore feed, and openpit mining.

In 2015, Northparkes’ E48 Lift 1 block cave mine became the world’s most automated underground mine with 100% automated loaders. The driverless loaders run themselves – moving and dumping the ore.

Production at E26 sublevel cave started in August 2016, with the aim of mining 2.9-million tonnes of ore with a 1.01% copper grade.

Brief History  
Copper and gold mineralisation was discovered at the E22 by Geopeko in 1976, the exploration arm of Peko-Wallsend, through road-side traverse drilling. Subsequently, the E27 and E26 deposits were discovered by drilling a grid of rotary air-blast drill holes in 1978 and 1980.

North Limited acquired the Northparkes project through its merger with Peko-Wallsend in the 1980s.

Following an extensive and lengthy studies phase, North approved the Northparkes project, comprising underground block cave and opencut mines and a concentrator, in 1992. North subsequently formed the Northparkes JV with Sumitomo Metal Mining Oceania and Sumitomo Corporation in 1993 to obtain a development partner with downstream smelting and refining capability.

Rio Tinto acquired North in 2000 and assumed management of the Northparkes JV.

In 2004, the second block cave mine, E26 Lift 2, was commissioned, with a northern extension added in 2008 (E26L2N), followed by initial production from E48 Lift 1 in 2010. In 2012, the nameplate mill throughput was increased to 6.4-million tonnes a year.

CMOC acquired Rio Tinto’s stake in the Northparkes JV in 2013. Fully automated mining and haulage was achieved from E48 in 2015.

In 2019, Northparkes celebrated its twenty-fifth year of production.

Primary Metals/Minerals  
Copper and gold.

Secondary Metals/Minerals  
Silver.

Geology/Mineralisation  
Northparkes is positioned in the Lachlan Fold Belt, one of Australia’s most prospective copper/gold belts.

The Northparkes deposits occur within the Ordovician Goonumbla volcanics of the Goonumbla Volcanic Complex and Wombin volcanics. The Goonumbla volcanics form part of the JuneeNarromine Volcanic Belt of the Lachlan Orogen and consist of a folded sequence of trachyandesitic to trachytic volcanics and volcaniclastic sediments, which are interpreted to have been deposited in a submarine environment.

The current life-of-mine plan is focused on five porphyries – E26, E48, E22, E31 and GRP314. In addition to these zones, several other mineralised porphyries exist across the district. The deposits are hosted within the Goonumbla and Wombin volcanics, with mineralisation-related intrusive rocks effectively forming part of the latter.

All the Northparkes deposits are crosscut by late faults/veins filled with quartz-carbonate and minor gypsum, anhydrite, pyrite, tennantite, chalcopyrite, sphalerite and galena, the associated sericite alteration can extend up to 10 m from the faults.

Reserves  
Ore reserves were estimated at 101.4-million tonnes grading 0.53% copper and 0.21 g/t gold as at December 31, 2022.

Resources  
Total mineral resources as at December 31, 2022, were estimated at 526.9-million tonnes grading 0.55% copper and 0.19 g/t gold.

Type of Mine
Opencut and underground.

Mining Method  
Current mining methods at Northparkes include underground block-caving and sublevel caving of the low-grade massive and reasonably large rock masses with suitable (caveability) properties.

Opencut mining has been used in the past and is planned for several small resources in the near future. Mining dilution is incorporated into the PCBC or opencut mine modelling and schedule.

PCBC is regarded as industry standard for block caving and has been used for production scheduling and draw management at Northparkes since the start of underground mining.

Major Infrastructure/Equipment  
Northparkes operations include:

• underground mining operations, decline and hoisting shafts;
• an overland conveyor to transport ore from hoisting shaft to the ore processing plant;
• an ore processing plant including surface crusher, crushed ore stockpiles, active grinding mills, froth flotation area and concentrate storage;
• tailings storage facilities;
• water management systems, which include watercourses, farm dams, settlement, retention and stilling ponds, the Caloola dams, the process water and return water dams;
• site offices, training rooms, a vehicle wash down area and workshop facilities, and
• significant electrical and water infrastructure between Parkes and Northparkes.

Prospects  
Evolution Mining announced in December 2023 that it would buy CMOC Group’s interest in the Northparkes mine.

Once the transaction is completed, Northparkes will add about 19 000 oz of gold and 12 500 t of copper to Evolution’s 2024 financial year guidance of 789 000 oz of gold and 62 500 t of copper.

Contact Details
Northparkes
Tel +61 2 6861 3000

Sources
Mining Weekly. Evolution seals $475m deal for iconic Northparkes mine (December 5, 2023).

Northparkes. Website: https://www.northparkes.com/
Northparkes. Northparkes Mining and Technical Information.
Northparkes. Memorandum NPM Resources and Reserves Statement as at 31 December 2022.