Volcan Compañía Minera S.A.A. is a subsidiary of Glencore AG, which is a subsidiary of Glencore Plc., owner of 63% of common class A voting shares and an economic interest of 23%, excluding treasury shares.
Volcan Compañía Minera S.A.A. and its subsidiary companies engaged in the mining sector operate the mining unit of Yauli.
In Q4 2022, Glencore commenced a process to dispose of its 23.3% economic interest in Volcan, which is ongoing. As a result, the carrying amounts of Volcan assets and liabilities as at 31 December 2023 and 31 December 2022 are classified as held for sale.
Summary:
The Yauli unit region shows mineralization related to polymetallic epithermal systems, replacement bodies and polymetallic vein systems, as well as porphyry mineralization and skarns, thus indicating the great potential of the area.
The two mining districts still in activity of the Yauli Dome area are Morococha to the northwest and San Cristobal-Andaychagua in the southern part of the Yauli Dome.
The southern portion of the Yauli Dome is the host of several vein-type and replacement mantles and bodies; including polymetallic deposits such as where Andaychagua, Carahuacra, San Cristobal and Ticlio are.
San Cristobal
Considered broadly, the Yauli Dome is the foremost structural feature of the San Cristobal region. This dome measures thirty kilometers by twenty kilometers. The long dimension strikes about N 40° W. The center of the Yauli Dome is formed by the Chumpe Anticline, the main structural feature of the San Cristobal area.
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.
Volcanic rocks in the area are fine to medium-grained with abundant quartz and plagioclase. Both limbs of the Chumpe Anticline show very different types of volcanic rocks. The northeast limb or Andaychagua side of the anticline has a variety of volcanic rocks which include andesites, basalt porphyries, tuffs, and dacites. The volcanic rocks on the southwest limb or San Cristobal side of the anticline are practically homogeneous throughoute The most common type is described as a quartz latite porphyry.
Carahuacra
The Carahuacra deposit lies on the southwest flank of the Yauli anticline, formed by Tertiary folding. Manto ore, formed before the climax of the Andean orogeny, consists mainly of ferroan sphalerite and pyrite, with negligible chalcopyrite. These were later brecciated tectonically to form two zones of 'breccia ore'. The last phase of mineralization involved formation of epithermal cross veins with sphalerite, pyrite, galena, tetrahedrite, and jamesonite, and irregular cementation of fragments in the breccia ore by sphalerite-galena and pyrite-marcasite. Supergene alteration, particularly pronounced in the breccia zone, has formed ore much enriched in silver (native silver, argentite, pyrargyrite).
Ticlio
The Ticlio intrusion (Cu-Au) in the western part of the Morococha district displays a zoned mineralisation and alteration pattern. A core of high-density stockwork of quartz-magnetite±K-feldspar veins changes progressively to an outer zone of intense Kfeldspar alteration with a low-density of magnetite and quartzmagnetite veinlets that host small amounts of bornite and native Au inclusions in chalcopyrite. An outermost zone displays a strong pyrite-quartz-sericitic alteration and skarn mineralisation in adjacent Cretaceous carbonate rocks.
Andaychagua
Andaychagua Vein is one of the producers in the San Cristobal district, is one of the most important veins on the southeast side of the Chumpe intrusive. The vein lies on the northeast side of the Chumpe Anticline* About three and a half kilometers southeast of the San Cristobal Vein system* The Andaychagma Vein strikes N 30° E and dips 85° northwest* The vein can be traced on surface for about four kilometers, three of which are in Mitu volcanic rocks and one of which in Excelsior phyHites. The structure continues on surface across the axial zone to the southwest side of the Chumpe Anticline, but only as a fault structure without apparent mineralization. The Andaychagua Vein carries sphalerite, galena, and silver minerals.
The 2023 drilling campaign aimed to enhance the geological certainty of mineral resources, utilizing infill drilling programs to upgrade indicated and measured mineral categories. Additionally, exploratory drilling sought to identify new economic resources and assess areas with promising geological and economic potential, thereby extending the longevity of the assets in the medium to long term.
At Andaychagua, efforts continued to refine the geological reliability of production plan sectors by reclassifying resources and incorporating new high zinc, lead, and silver mineral reserves in various extensions. Furthermore, significant economic mineralization was confirmed at the Valentine and Catherine veins, ensuring strong performance and an extended Life of Asset (LoA).
At San Cristóbal, the drilling programs yielded positive results, leading to the inclusion of economic mineral resources in various veins as primary sources of zinc and silver mineralization. The discovery of new polymetallic bodies and mantles further expanded the operational perspective for the medium to long term. Karaouacre also reported the presence of high zinc, lead, silver, and copper mineral resources, with continuity of economic mineralization confirmed in specific areas.
Regarding Ticlio, efforts focused on deepening the Ramal Teho vein to bolster geologic credibility and delineate new economic resources. The exploration of additional high potential areas aimed to solidify discoveries in the coming years. Geochemical results highlighted promising prospects for the continuity of the Ticlio mine, ensuring sustained operations.