Yauricocha is a carbonate-replacement ore deposit.

The Yauricocha mining district contains multiple polymetallic deposits represented by skarn and replacement bodies and intrusion-hosted veins related to Miocene-era magmatism. Mineralization is strongly structurally controlled with the dominant features being the Yauricocha Fault and the contact between the Jumasha limestones and the Celendín Formation (especially the France Chert).

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 style (manto) deposits to narrow, sub-vertical chimneys. The mineralization features economic grades of silver (Ag), copper (Cu), lead (Pb) and zinc (Zn), with local gold (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 is associated with Cu-rich bodies.

Mineralization of the Yauricocha deposit is formed principally of pyrite, quartz, enargite, chalcopyrite, bornite and covellite in the core and central parts of the bodies. Loose masses of friable pyrite, galena, sphalerite and minor amounts of chalcopyrite in a gangue of limestone, clay and quartz occur in the periphery of the bodies. Native gold is associated with the sulfide minerals. Mineralogical zoning of the district is marked, with the core of the central part consisting of enargite located within the Jumasha limestone near the contact with the France Chert. Next to the west are rich bodies of bornite and chalcopyrite with predominance of enargite. Further to the west occur rich bodies of lead, zinc, silver and gold. The same zoning is observed at a smaller scale inside the ore body.

The mine production areas are grouped into six mining areas: Mina Central, Esperanza, Mascota, Cuye, Cachi-Cachi, and Cuerpos Pequeños. Sub-level caving is the primary mining method at Yauricocha representing 84% of the production. This method is in use Mina Central, Esperanza, Mascota, and Cuye. Sub-level caving and overhand cut and fill is used for Cachi-Cachi, and overhand cut and fill is used for Cuerpos Pequenos.

Sub-level caving is comprised of three sub-levels that are established for each 50 m level resulting in a planned 16.7 m between sub-levels labeled as pisos (floors). Material is caved from the sublevels and recovered in a drawpoint. Drawpoints from the footwall into the ore are typically 3.5 m wide x 3.0 m high and are spaced 8.0 m apart. Steel sets, shotcrete and bolting are used as ground support in the drawpoints and the length of each drawpoint varies with the thickness of the orebody. As the drawpoint is developed, ore samples are collected for grade control analysis from the left and right ribs. Upholes are drilled in stopes to initiate caving. Effective draw control is an important to successful extraction for this mining method. Drawpoints are staggered by 4.0 m from sub-level to sub-level.

Cut and fill mining is employed in the smaller orebodies. Typically, the cuts are mined 2.0 m wide x 3.0 m high in an overhand (ascending) technique where the lower levels are filled as mining progresses to the next sub-level above. Sill pillars are left between levels as mining comes up underneath the previously mined level. Based on geotechnical constraints the sill pillars are typically a minimum of 3.0 m in thickness.

Polymetallic sulfide ore accounts for more than 99% of the material mined at Yauricocha. Material classified as lead oxide can also be encountered, but it is a minor component of the overall tonnages in the reserves estimate.

The mine is accessed by two shafts, Central Shaft and Mascota Shaft, and the Klepetko and Yauricocha tunnels. Ore and waste are transported via the Klepetko Tunnel at the 720 level (elevation 4,165 masl) which runs east-northeast from the mine towards the mill and concentrator, and the 4.7 km Yauricocha Tunnel, commissioned in 2018, that also accesses the mine at the 720 level. The Yauricocha Tunnel was added to increase haulage capacity and serves as a ventilation conduit.

The Yauricocha Shaft, currently under construction, will provide access down to 1370 level and is expected to be in operational in 2022.

Mine production at Yauricocha is currently an average of 3,300 t/d with planned annual production of 1.2 million tonnes per year (Mt/y) for 6 years.

Ore is processed at the on-site Chumpe plant using a combination of crushing, grinding and flotation and is permitted to produce at a rate of 3,150 tpd, which we expect to increase to 3,600 tpd during 2020 upon receipt of the ITS permit.

Yauricocha operates a conventional concentration process that includes two parallel circuits to process polymetallic ore and oxide ore. Each circuit consists of a crushing stage, grinding, sequential differential flotation, dewatering of the concentrates, thickening and disposal of the flotation tails. The Yauricocha plant currently produces three mineral concentrates: lead sulfide concentrate, copper sulfide concentrate, and zinc concentrate.

Yauricocha polymetallic circuit has a nominal capacity of 3,000 t/d. The polymetallic plant is showing a consistent upward trend in throughput capacity. During the January to October 2019 period, the polymetallic circuit operated on average at 2,926 t/d of fresh feed. Silver is preferential ........