Constancia mine include the Constancia and Pampacancha deposits

CONSTANCIA
The Constancia deposit is a porphyry copper-molybdenum system which includes copper-bearing skarn mineralization. Multiple phases of monzonites and monzonite porphyry have intruded a sequence of sandstones, mudstones and micritic limestone of Cretaceous age.

The majority of the mineralization is associated with potassic alteration and quartz veining, occurring as chalcopyrite-(bornite)-molybdenite-pyrite mineralization in “A” and “B” type veinlets, and replacing ferromagnesian minerals or filling fractures. Copper grades are highest where fracture-filling style copper mineralization is superimposed on earlier disseminated copper mineralization. The higher-grade hypogene copper mineralization is hosted by a dense A-veinlet stockwork developed in an early porphyry phase. The pyrite/chalcopyrite ratio is typically below 2:1. Molybdenite commonly increases with depth in association to “B” veinlets. Bornite occurs sporadically especially at deeper levels, sometimes associated with some gold values.

Propylitic alteration is transitional to the potassic alteration and extends more than one kilometre from the porphyry intrusive contacts. The propylitic alteration mineral assemblage includes epidote-chlorite-calcitepyrite-rhodochrosite. Subordinate chalcopyrite is also present, filling fractures or replacing mafic minerals. Sphalerite-galena veinlets and veins ar ........

The Constancia mine is an open pit mining operation relying on conventional trucks and shovels. The Constancia ultimate pit design will measure approximately 1.6 km east to west, 1.7 km north to south, and have a maximum depth of around 705 m. The Pampacancha ultimate pit design will measure approximately 0.6 km east to west, 1 km north to south, and have a maximum depth of about 300 m. A primary waste rock facility (WRF), which is located to the south and east of the Constancia pit, is intended to be used for both deposits.

The processing facility is located approximately 1 km west of the Constancia Pit. The NAG waste rock is deposited south of the Constancia pit, while the tailings management facility (TMF) is located 3.5 km southwest of the Constancia pit.

DESIGN CRITERIA
Constancia is mined in nine stages and a two stage pit is planned at Pampacancha. The minimum mining width for each phase is 60 meters; this will allow a shovel, trucks (in two lines) and a drill to work safely and simultaneously.

The haul roads at Constancia and Pampacancha have been designed with a 10% grade and 32 m width for double lane haul roads and 24 m for single lane haul roads.

The final design for waste rock facilyty facility incorporates 20 m high benches with 1.4H:1V (36°) of bench slopes and 32 m wide benches. The overall slope of the stockpile will be about 3.0H:1V (18°). The current remaining capacity of the WRF is estimated ........

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