The Yauli dome is located 100km east of Lima, Peru. The southern portion of the dome is where Andaychagua, Carahuacra, San Cristobal and Ticlio are located, and is made up of mantos and vein-type deposits. The mantos are hosted by the Pucara limestone, while the veins are steeply dipping and cross-cut rocks of the Mitu and Excelsior groups, as well as the Chumpe and San Cristobal intrusions.

(Translated from Spanish by Google Translate)
Carahuacra underground Mine is a part of Yauli unit.

There was an increase in the head grades of silver and lead by 25% and 4%, respectively. However, zinc and copper head grades decreased by 20% and 3%, respectively. The programmed laws were not reached due to the delays in the primary and secondary developments of 2020, product of the impact of the covid-19.

The volume of production contribution was 23% higher than in 2020, due to the contribution of the veins in the main mantle systems, Lourdes, Fátima, Susana and Mary's part. The results of production of fines in zinc, lead and silver were above 2020 by 1%, 29% and 63%, respectively.

In this area, mining is consolidated using the OCF method utilizing Hydraulic backfill.

Seismic events occurred in the Mary vein, which paralyzed its production contribution for a period of three months. In this period the cable installation was implemented bolting and additional support to secure the mine with a greater safety factor.

Diamond drilling exploration was directed towards mantle systems main, Mary, Lourdes, Susana, Manto Poderosa, Fátima and Jazmín vein in the levels 870, 920, 970, 1070, 1180, 1220, 1360. Likewise, on the surface the vein Kindness, where it was possible to recategorize indicated resources to measured ones.

Andaychagua's processing plant include grinding circuit consist of primary ball mills #1, 2 (10.5 'x 14', 8 'x 10') and secondary grinding ball mill (7’ x 12’).

(Translated from Spanish by Google Translate)
Currently, four underground mines operate: San Cristóbal, Carahuacra, Andaychagua and Ticlio, whose extracted ore is treated in two concentrator plants, Victoria and Andaychagua, with an installed capacity of 8,650 tpd. The Mahr Tunnel Plant with a capacity of 2,750 tpd is in care & maintenance.

Victory plant
The Victoria concentrator plant has an available processing capacity of 5,300 tpd. During 2021, the flow sheet in zinc flotation was modified to implement the RCS-100 and RCS-30 cells in the Rouger, Scavenger and Cleaner circuits, with the aim of improving the recovery and increasing the quality of the concentrate of zinc.

The following recoveries were achieved: zinc 94.5%, lead 83.3% and silver 87.0%; in the 2021, which represent an increase in zinc by 3%, silver by 2% and a decrease in lead by 0.4% compared to 2020.

Likewise, the silica content in zinc concentrates was reduced, which allowed ........