Las Cruces is a high-grade open-pit copper mine and hydrometallurgical
plant, owned and operated by Cobre Las Cruces S.A., a wholly-owned
subsidiary of First Quantum Minerals Ltd. Las Cruces is located
approximately 20 kilometers northwest of the city of Seville, in the Seville
Province of southern Spain.
Construction of the mine was completed in 2008 and the process plant was
completed in February, 2009. In June 2009, Las Cruces produced the first
copper cathode.
The Las Cruces deposit is a polymetallic volcanogenic massive sulfide
deposit, similar to other Iberian Pyrite Belt deposits. A thick, high-grade
supergene zone overlies the primary sulfides, comprised of a gold-bearing
gossan zone in the upper part and a copper-rich secondary sulfide zone
underneath.
Las Cruces uses conventional open-pit mining methods, based on hydraulic
excavators and trucks, with drilling and blasting in the lower marls and ore
zones. Ore undergoes three stages of crushing, a single-stage of grinding
and is thickened to eliminate water before it goes to three pre-reactor
tanks.
The hydrometallurgical plant relies on a unique atmospheric ferric leaching
process to recover copper from the rich Las Cruces chalcocite ore. The
process, specifically designed for Las Cruces polymetallic ore, is optimized
to produce London Metal Exchange (LME) grade copper cathode with minimal
water and energy use, controlled liquid effluent and a dry solid waste
stream.
The plant is designed to produce approximately 72,000 tonnes of copper
cathode per year which is shipped as final product.