Name: Las Cruces mine.

Location: The mine is located in Sevilla, in Southern Spain.

Mine Owner/s: Cobre Las Cruces (CLC), a wholly owned subsidiary of First Quantum Minerals.

Brief Description: The Las Cruces mine is a copper mining complex with an openpit mine and hydrometallurgical process plant. The mine has one of the world’s richest copper deposits.

Brief History: The Las Cruces deposit was original discovered by Rio Tinto in 1994, as a result of drilling on a gravimetric survey anomaly. Rio Tinto drilled the deposit between 1994 and 1999 and prepared a feasibility study in 1998.

In 1999, MK Resources Company acquired the project and established CLC as the local Spanish subsidiary company. The mining concession was granted in August 2003.

Geology/Mineralisation: The Cobre Las Cruces deposit occurs in the eastern end of the Iberian pyrite belt, a 300-km-long and 80-km-wide geological belt that extends eastward from southern Portugal into southern Spain. The belt is host to more than 100 mineral deposits, some of which were exploited for metals as long ago as the Bronze Age. Mineralisation comprises syngenetic massive sulphides containing polymetallic mineralisation, similar to most other Iberian pyrite belt deposits. Cobre Las Cruces is a blind deposit with no outcrop because of the 100 m to 150 m of sedimentary marls overlying the deposit. No other deposits have been found in the immediate area, but exploration is difficult because of the thickness of the overburden. The nearest deposits are Aznalcollar and Los Frailes, both about 10 km to the west in the area where the host rock assemblage outcrops at the surface. The Aznalcollar and Los Frailes deposits comprise lead and zinc massive sulphides that were in production over the last 10 to 20 years. The massive sulphide mineralisation on the property is hosted by late Devonian to early Carboniferous period volcanic and sedimentary rocks deposited in a submarine setting within a narrow and relatively shallow intracontinental sea and characterised by bimodal volcanism and sedimentation. Post depositional secondary copper enrichment occurred in the upper part of the massive sulphide deposit, forming the secondary mineralisation of interest. The deposit was subsequently buried under 100 m to 150 m of sandstone and calcareous mudstone, called marl.

Mining Method: Las Cruces uses conventional openpit mining methods, based on hydraulic shovels and trucks, with drilling and blasting in the lower marls and ore zones.

Major Infrastructure and Equipment: The operation comprises an openpit and a hydrometallurgical plant, which is one of the most technologically advanced in the world for treating copper. The use of optimised applied process technology maximises the reuse of water, energy and material resources.

CLC uses a process known as ‘clean technology’, which results in the copper produced being ready for sale directly from the plant.

The metallurgical plant relies on an atmospheric leaching process to recover copper from the rich Las Cruces chalcocite ore. A unique feature of the plant is the use of eight OKTOP agitated reactors to dissolve the copper under conditions of high temperature and high acidity. Oxygen is also added into the reactors to complete the reaction. The feed to the leaching reactors is mine ore that has passed through three stages of crushing and a single stage of grinding.

Products: Copper.

Reserves: Total proven and probable reserves as at December 31, 2017, were estimated at 4.3-million tonnes grading 4.54% copper.

Resources: Total measured and indicated resources in the secondary sulphide category as at December 31, 2017, were estimated at 3.9-million tonnes grading 5.59% copper. Total measured and indicated resources in Gossan are estimated at 800 000 t grading 1.71 g/t gold, 2.09% lead and 42.36 g/t silver. Primary sulphide resources are estimated at 36-million tonnes grading 1.11% copper, 1.25% lead, 28.94 g/t silver and 2.64% zinc.

Prospects: CLC has obtained the necessary regulatory approvals for the start of mining of Phase 6 of the operation.

Contact Details:
Cobre Las Cruces
Tel + 955 657 950
Email comunicacionclc@fqml.com