The Yauricocha Mine features several mineralized bodies, which have been emplaced along structural trends, with the mineralization itself related to replacement of limestones by hydrothermal fluids related to nearby intrusions. The mineralization varies widely in morphology, from large, relatively wide, tabular manto-style deposits to narrow, sub-vertical chimneys. The mineralization features economic grades of Ag, Cu, Pb and Zn, with local Au to a lesser degree. The majority of the deposits are related to the regional high-angle NW-trending Yauricocha fault or the NE-trending and less well-defined Cachi-Cachi structural trend. The mineralization generally presents as polymetallic sulfides but is locally oxidized to significant depths or related to more Cu-rich bodies.

Goyllarisquizga Formation
The oldest rocks exposed in the area are the lower Cretaceous Goyllarisquizga arenites. This formation is approximately 300 m thick and comprises thick gray and white arenites, locally banded with carbonaceous lutites as well as small mantos of low-quality coal beds and clay. In the vicinity of Chaucha, these arenites have near their base interbedded, red lutite. The arenites crop out in the cores of the anticlines southwest of Yauricocha, as beds dispersed along the Chacras uplift, and isolated outcrops in the Éxito zone.

Jumasha Formation
The mid-Cretaceous Jumasha Formation consists of massive gray limestone, averages 700 m thick, and concordantly ove ........

The Yauricocha Mine is a producing operation with a long production history. Most of the mining is executed through mechanized sub-level caving with a relatively small portion of the mining using overhand cut and fill. The mine uses well-established, proven mining methods and is planning to increase the production rate to 5,500 tpd (2.0 Mt/y) in 2024.

Mechanized sub-level caving (SLC) and overhand mechanized cut and fill (MCF) mining methods are currently used in the mine to achieve production with most of the production by SLC mining methods.SLC is the primary mining method at Yauricocha, representing 84% of the annual production.

SLC mining areas have historically been established by developing three sub-levels for each 50m main level via ramps. This results in a planned 16.7 m sub-level spacing which are called pisos (floors). Below the 1070L, main level spacing will be increased to 100m, but the sub-level spacing remains the same. One aspect of modernizing the SLC practices will be to work towards increasing the sub-level spacing to 25 m which is typical of modern SLC mines. Geotechnical work and trial mining will be conducted as part of the program to phase in this change. Not all mineralized bodies will necessarily be converted due to geotechnical constraints.

On each sub-level, drawpoints are developed from the footwall to the hangingwall of the mineralized body, typically at 3.5 m wide x 3.0 m high and are spaced 8.0 m apart along the ........

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Yauricocha operates a conventional, multi-stage differential flotation plant that includes two parallel processing circuits, one to process polymetallic mineralized material, and the second to process oxide mineralized material. Each processing circuit consists of a crushing stage, grinding, sequential differential flotation, dewatering of the concentrates, thickening and disposal of the flotation tails.

Yauricocha’s original combined capacity of the two processing circuits totals 3,600 tonnes per day. The polymetallic circuits nominal capacity has historically been 3,000 tonnes per day and the oxide circuit 600 tonnes per day, however ongoing improvements to the circuits have been increasing daily throughput.

No oxide mineralized material has been processed since 2018 and current plant production includes only three mineral concentrates: lead sulfides concentrate, copper sulfides concentrate, and zinc concentrate.

Recent improvements to the processing ........