Mineralization in the Nuestra Señora area includes mineralized calc-silicate skarns, carbonate replacement deposits, veins, and breccia-hosted deposits that occur within limestone and granodiorite. Pb-Zn-Cu-Ag mineralization is primarily associated with variably retrograde-altered garnet-pyroxene exoskarn with lesser mineralization within pyroxene-garnet endoskarn in the Nuestra Señora mine. Within the Nuestra Señora Main Zone, post-skarn brecciation and calcite emplacement appear to be contemporaneous with mineralization, with sulfides occurring as fracture-fill and large “clots” within the calcite-filled breccia matrix.

Pb-Zn-Cu-Ag mineralization at Nuestra Señora is primarily associated with variably retrograde-altered garnet-pyroxene exoskarn (bedded limestone protolith) with lesser mineralization within pyroxenegarnet endoskarn. In general, exoskarn mineralization occurs within preferential horizons in the general stratigraphy which strikes northwest and dips to the northeast 30-50o. Thrust faulting sub-parallel to bedding has been proposed to create more favorable fluid pathways and localize mineralization.

Within the Nuestra Señora Main Zone, post-skarn brecciation and calcite emplacement appear to be contemporaneous with mineralization, with sulfides occurring as fracture-fill and large “clots” (up to 10cm across) within the calcite-filled breccia matrix. The breccia texture can be coarse with clasts greater than one meter in width. Though ther ........

In December 2017, the Nuestra Señora mine was placed on care andmaintenance. Production from the Nuestra Señora mine has stopped although a resource remains at the property.

Nuestra Señora underground mine development commenced in 2005, and prior to the commissioning of the process plant in May 2008, approximately 87,000 tonnes of ore had been stockpiled on surface. Since attaining commercial production of the process plant in January 2009, the Nuestra Señora mine has been the sole source of ore feed for the plant. Mining at Nuestra Señora uses mechanized mobile mining equipment, principally twin-boom jumbos, 6yd3 scoop trams, production drill rigs, and rigidbody highway trucks.

Complex geometries of the mineralized bodies make it imperative to employ high-density definition drilling techniques to determine the extents of the mineralization. During development, ore-control definition is performed by drilling 12m long holes on approximately 4m centers. Samples are taken from the cuttings of each 1.5m of drill steel and are assayed in the operation’s laboratory. This detailed sampling control allows for more appropriate development, improving mining recovery and minimizing dilution.

As successive levels are developed, each mineralized body is tested for continuity and size. The mining method employed for each mineralized body is determined by its geometry. Predominantly long-hole or cut-and-fill stoping is designed for production; however, sh ........

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