There are two types of deposits in the San Cristobal district, veins and mantoso Veins are roughly perpendicular to the axis of the Chumpe Anticline and mantos are emplaced along the Mitu volcanic rocks-Paria limestone contact.

The San Cristobal Vein system is made up of two main mineral-bearing structures, the San Cristobal Main Vein and the Siberia 1 Vein, The Oyama-Triunfo Vein, which is located on the northeast limb of the anticline, appears to be an extension of the San Cristobal Main Vein, Both veins are separated on the surface by Chumpe lake and no underground workings exist below the area that permit a clear correlation.

The San Cristobal Main Vein extends all the way along the San Cristobal fault, considering the Oyama-Triunfo Vein as its extension. The Siberia 1 Vein is located in the axial zone of the anticline# At present the San Cristobal mine is working in the San Cristobal Main Vein. This vein is well known underground and carries zinc, lead, copper, and silver minerals and locally tungsten minerals. The Siberia 1 Vein is little known in underground workings and carries mainly tungsten mineralization.

Andaychagua is an underground mine, a part of Yauli unit, which is located between altitudes of 4,000 and 4,900 m.a.s.l. in the region of Junin, 40 km from the city of La Oroya and 170 km from Lima. The unit is made up of four underground mines and an open pit, whose mineral is treated in three concentration plants, with an installed capacity of 11,400 TPD.

Sub-level stoping is utilized as a primary mining method.

Currently, the extracted ore is treated in three concentrator plants: Victoria, Mahr Tunel and Andaychagua, with a total installed capacity of 11,400 tpd.

Victoria concentrator plant
The operation of the Victoria concentrator plant is automated, including Courier online analysis systems and a control system that regulates the ratio of water to ore during the milling process. It is worth highlighting that the Victoria concentrator plant can separate low-grade lead and copper concentrates by flotation.

During 2019, the capacity of the Victoria concentrator plant to process 5,200 tpd was maintained. As a result, production from the Victoria plant represented 42% of treated tonnage for the Yauli UEA.

Selective zinc flotation was implemented, eliminating 100% of the use of lime in the flotation process, thereby lowering the flotation costs, lowering the ratios of the main reagents (CuSO4 from 0.38 to 0.34).

Copper flotation in the bulk circui ........