Name of the Mine
Gibraltar mine.

Location  
South-central British Columbia, Canada.

Mine Owner/s  
Taseko (75%) and Cariboo Copper Corp (25%).

Brief Description  
Gibraltar is the second-biggest openpit copper mine in Canada and the fourth-biggest in North America. It comprises 32 mining leases covering 2 275 ha, 215 mineral claims covering 21 425 ha and five optioned claims covering 2 888 ha.

Since restarting the mine in 2004, Taseko has expanded and upgraded the operation. It is now an award-winning, state-of-the-art facility that produces an average of 130-million pounds of copper a year.

The operation has a 23-year mine life.

Brief History  
Mining started at Gibraltar in 1971.

Taseko acquired its interest in the assets of Gibraltar in a transaction with Boliden in July 1999. After being under care and maintenance for a while, mining operations restarted in May 2004, with milling production starting in October the same year.

Taseko established a joint venture with Cariboo Copper Corp over the Gibraltar mine on March 31, 2010, whereby Cariboo acquired a 25% interest in the mine and Gibraltar retained a 75% interest.

Primary Metals/Minerals  
Copper/molybdenum.

Secondary Metals/Minerals  
Silver.

Geology/Mineralisation  
The Gibraltar openpit mine is a calc-alkalic porphyry copper/molybdenum deposit entirely hosted by the Late Triassic Granite Mountain batholith, a component of the Quesnel volcanic arc terrane.

The Granite Mountain batholith is a composite body comprising three major phases: Border Phase diorite, mine phase tonalite and Granite Mountain trondhjemite.

Mineralisation occurs predominantly in the mine phase tonalite. Contacts between the major phases are gradational over widths ranging from 2 m to several hundred metres.

According to Glencore’s March 2022 ‘Gibraltar Technical Report’, there are currently five defined mineralised zones on the property – Granite, Pollyanna, Connector, Gibraltar and Extension. They occur in a broad zone of shearing and alteration. Two major ore structure orientations have been recognised – the Sunset and Granite Creek systems. Ore host structures of the Sunset system are mainly shear zones, with minor development of stockworks and associated foliation lamellae, whereas oriented stockworks with associated pervasive foliation lamellae predominate in the Granite Creek system.

Copper ore at Gibraltar typically occurs in potassic and ankeritic hydrothermal mineral assemblages, predominantly as disseminated and vein-hosted chalcopyrite mineralisation. Pyrite and chalcopyrite are the principal primary sulphide minerals.

There are small concentrations of other sulphides in the Gibraltar ores, with molybdenite being a minor, but economically important associate of chalcopyrite in the Pollyanna, Granite and Connector deposits.

Reserves  
Total proven and probable reserves as at December 31, 2021, were estimated at 706-million grading 0.25% total copper and 0.008%.

Resources  
Total measured and indicated resources 1.22-billion tons grading total copper 0.24% and 0.26% molybdenum. Inferred resources 78-million tons.

Mining Method  
The Gibraltar deposits have been developed using openpit mining methods and conventional openpit mining equipment.

Major Infrastructure/Equipment  
The processing facilities at Gibraltar mine comprise two separate bulk sulphide concentrators, a dedicated molybdenum flotation plant and a series of oxide leach dumps that feed a solvent extraction and electrowinning facility.

Other facilities that support the current operating activities include:

• access to utilities that include electrical power, natural gas and domestic-use water; 
• existing processing facilities to extract final saleable products from the sulphide and oxide ores;
• waste storage facilities for mine waste rock and an existing tailings storage facility;
• on-site support, maintenance and administration facilities;
• a complete set of water management infrastructure covering water collection, storage and discharge at prescribed water-quality requirements; and
• concentrate-handling facilities and existing off-site sale supply chains.

Prospects  
Not stated.

Contact Details
Taseko
Tel +1 778 373 4533
Email Investor@tasekomines.com
Website https://www.tasekomines.com/

Sources
Taseko. Technical report on the mineral reserve update at the Gibraltar mine (March 20, 2022).
Taseko. Website: https://www.tasekomines.com/ [accessed June 12, 2022].