Name of the Mine
Eloise mine.

Location
The mine is located in north Queensland, in Australia, about 60 km south-east of Cloncurry and 155 km east-south-east of Mount Isa.  

Mine Owner/s
AIC Mines.

Brief Description
The Eloise mine is a high-grade underground mine.

Brief History
The Eloise deposit was discovered by BHP in 1988, with Amalg Resources acquiring it from BHP in 1994. First ore was mined in April 1996.

Amalg merged with Breakaway Resources in 2003, and a year later Barminco Investments – which would change its name to FMR Investments in 2011 – bought the mine.

From 1996 to 2021, the mine produced 339 000 t of copper and 167 000 oz of gold.

AIC completed its acquisition of Eloise on November 1, 2021.

Primary Metals/Minerals
Copper and Gold.

Secondary Metals/Minerals
Silver.

Geology and Mineralisation
The Eloise deposit is hosted by a sequence of Proterozoic basement lithologies concealed beneath 60 m of flat-lying Mesozoic sediments.

The host rocks predominantly comprise arenitic metasediments and amphibolites. The main copper-bearing sulphide at Eloise is chalcopyrite, with pyrite and pyrrhotite as the dominant gangue sulphides.

Mineralised zones occur as steeply plunging lenticular bodies with strike lengths between 100 m and 200 m, and attaining a maximum width of 25 m.
The main zone of mineralisation (Levuka-Eloise Deeps) demonstrates continuity down plunge over 2 000 m and remains open at depth.

Reserves
The Eloise mine had a total ore reserve of about 2.2-million tonnes grading 2.4% copper, 0.6 g/t of gold and 8.8 g/t of silver, containing about 52 600 t of copper, 43 100 oz of gold and about 620 700 oz of silver, as at December 31, 2022.

Resources
As, at December 31, 2022, the mine had a total mineral resource estimate of 5.7-million tonnes, grading 2.4% copper, 0.6 g/t of gold and 9.8 g/t of silver, containing about 137 200 t of copper, 118 800 oz of gold and about 1.8-million ounces of silver.

Type of Mine
Underground.

Mining Method
The upper levels of the mine are extracted using longhole open stoping and the deep levels are extracted using sublevel caving.

Major Infrastructure/Equipment
The Eloise site comprises four mining leases covering about 505.9 ha. It is accessible by sealed road.

The underground workings are ventilated using two downcast shafts, the access decline and a primary exhaust shaft.

The two bulk air-cooling units on surface are used to maintain a safe operating temperature.

The underground fleet comprises seven 60 t Sandvik TH663 trucks, three Caterpillar loaders and a Caterpillar grader, among other equipment. On the surface, the mine uses two Volvo loaders, a Bobcat skid steer, a Volvo excavator, two forklifts, a fire truck, a 21-seater bus, a service truck and a Tadano crane.  

Mining contractor Pybar’s fleet includes two Sandvik development drills, two Sandvik loaders, two Caterpillar trucks, a shotcrete spray rig and a concrete agitator truck.

It has a conventional concentrator with three-stage crushing, primary and secondary ball milling, three-stage flotation and dewatering to produce a copper/gold/silver concentrate. The plant’s current capacity is estimated at 725 000 t/y.

The mine also has on-site diesel generators, an accommodation village and an established borefield with an allocation of about 355-million litres a year.

It has five tailings dams – two have reached capacity, two have been decommissioned and the fifth was commissioned in May 2023 and can provide five years’ worth of tailings storage capacity without lifts at the current processing capacity, and up to ten years’ worth of capacity with lifts.

Prospects
In September 2022, AIC Mines launched an off-market takeover offer for all Demetallica’s shares in Sepetember 2022. The offer closed successfully on December 5, 2022.

Through the acquisition, AIC gained ownership of the Jericho copper deposit, 4 km south of the Eloise processing facility. Demetallica also held more than 2 000 km² in exploration tenements in the area surrounding the Eloise mine.

AIC has described the development of Jericho as “transformational” for Eloise, as it offers the potential to increase yearly production to more than 20 000 t of copper and 10 000 oz of gold in concentrate; helps to reduce all-in sustaining costs by leveraging economies of scale; reduces reliance on the Eloise Deeps deposit, thereby derisking ore production; and extends the mine life.

In May 2023, AIC cited its main capital expenditure items for the 2024 financial year, including two truck rebuilds; the replacement of two underground loaders – although it is considering lease alternatives and hire purchase options; underground development at Eloise of about $25-million; resource definition drilling at Eloise for between $5-million and $6-million; and chiller and ventilation upgrades.

AIC was also considering plant expansion options to increase throughput from one-million tonnes a year to 1.4-million tonnes a year. GR Engineering Services was appointed to complete the expansion optimisation study.

In the AGM Shareholder Update on November 22, 2023, AIC noted that, in the 24 months in which it has owned Eloise, the mine had produced 23 380 t of copper in concentrate and completed “significant” refurbishment of its mining fleet.  AIC had also discovered the “very high-grade” Lens 6 deposit on the Eloise mining lease area, which, alongside the development of Jericho, will have a material impact on Eloise’s mine life and economics.

Contact Details
AIC Mines
Tel  + 61 (8) 6269 0110
Email info@aicmines.com.au or ecmadmin@aicmines.com.au

Sources
AIC Mines. https://www.aicmines.com.au   
AIC Mines. Eloise Copper Mine.
AIC Mines. Transformational Acquisition AIC to Acquire the Eloise Copper Mine (August 31, 2021).
AIC Mines. Investor Presentation (February 2022).
AIC Mines. Eloise Copper Mine Almanac (May 2023).
AIC Mines. AGM Shareholder Update (November 22, 2023).