Inca Minerals Limited (ASX: ICG) has announced the discovery of visible copper mineralisation at the new ground within its existing Uchpanga III mining concession at the Riqueza project in Peru, South America.
The company said that the formerly excised part of Inca’s Uchpanga III mining concession (Uchpanga III) has reverted to Inca and a brief mapping and sampling program (7 rockchip samples) was undertaken in the recently added part of Uchpanga III.
Inca announced that discrete zones of copper (Cu), silver (Ag), and molybdenum (Mo) mineralisation were discovered at Uchpanga III with peak Cu 4.54% in sample BM-00956, peak Ag 97g/t in sample BM-00992, and peak Mo 192.01ppm in sample BM-00992.
The company said that a similar brief mapping and sampling program (20 rockchip samples) undertaken in the SW Corner revealed widespread hydrothermal activity and epithermal/porphyry related alteration.
The Riqueza project is a Zn-Ag-Pb-Au-Cu focused project located within a part of Peru’s Miocene Porphyry-skarn Mineral Belt. This northwest-southeast belt hosts numerous porphyry and skarn deposits, several large mines, and dozens of smaller mines.
The Riqueza Project area comprises Peruvian mining concessions: Nueva Santa Rita, Antacocha I, Antacocha II, Rita Maria, Maihuasi, Uchpanga, Uchpanga II, Uchpanga III, and Picuy.
Uchpanga III mining concession expansion
In 2016, the Company felt it possible that mineralisation being uncovered on the Nueva Santa Rita mining concession might extend to the south. Five mining concession applications were lodged east and south of Nueva Santa Rita.
One such application, Uchpanga III―the southernmost, partly extended across an existing mining concession owned by another party. The part where Uchpanga III overlapped this existing concession was not awarded to Inca when Uchpanga III was granted in July 2016.
However, because of the older mining concession recently expiring, the overlapped area has now been incorporated into Inca’s Uchpanga III mining concession. This new area is now been referred to as the Uchpanga Enclave.
Mapping and sampling at Uchpanga Enclave
The company had recently undertaken a brief mapping and sampling program (7 rockchip samples) at Uchpanga Enclave, the recently added part of Uchpanga III.
ICG said that the mapping within the Uchpanga Enclave was warranted because the area has not been mapped and sampled by Inca previously. In addition, the areas immediately west, north, and east of the enclave, within the Riqueza Project area, host multiple important large-scale epithermal and porphyry drill targets.
The company has now reported encouraging results from the brief mapping and sampling in the new Uchpanga Enclave.
Two new zones of highly-altered Cu-Ag-Mo mineralisation
The company reported that the brief mapping and sampling in the new Uchpanga Enclave has identified two new zones of highly altered copper-silver-molybdenum mineralisation associated with distinct structural/breccia zones.
ICG noted that phyllic alteration has undergone argillic overprinting. The company said that the visible Cu mineralisation is in the form of massive to disseminated secondary copper, including the ore-forming minerals malachite, azurite, and chrysocolla. These occur with alteration minerals, quartz, sericite, limonite, and jarosite.
Inca Minerals said that the mineralisation and alteration assemblage of the enclave is very similar to the immediate surrounding areas and, like the surrounding area, display epithermal/porphyry characteristics.
The company said that the assay results of the seven samples indicate strong Cu, Ag, and Mo mineralisation in two areas.
Notable assay results include Sample BM-00956 contains 4.54% Cu and 50.00g/t Ag over 0.65m; Sample BM-00957 contains 3.48% Cu and 82.00g/t Ag over 0.45m; Sample BM-00991 contains 1.33% Cu, 72.00g/t Ag and 65.41ppm Mo over a 10m x 4m area (float dump material from an old mine workings); and Sample BM-00992 contains 0.11% Cu, 97.00g/t Ag and 192.01ppm Mo.
New drill targets
The company announced that the two Cu-Ag-Mo outcrop areas in the Uchpanga Enclave are considered drill-worthy and will be added to the existing list of 29 targets.
ICG said that as they occur in the southern part of the project, they will be made part of the DIA drill permit. The company said that the drill permitting process for the NE Area, under an FTA permit, will not be delayed by these additional targets.
Mapping and sampling at SW corner
The company had recently mapped and sampled the SW Corner of Riqueza (20 rockchip samples), in the vicinity of the proposed drill holes RP28 and RP29.
These areas host vegetation anomalies, believed to be related to high levels of sulphide mineralisation. The company said that as the area had not been mapped by Inca, and because the field geologists had mobilised to map the Uchpanga Enclave, the SW Corner was added to the field program.
Widespread hydrothermal activity and epithermal/porphyry related alteration
Inca said that the mapping has identified widespread quartz-calcite±barite veins, veinlets and stockworks and brecciation within a phyllic and propylitic altered sequence of volcanic sequence, indicative of pervasive hydrothermal activity associated with possible proximal epithermal and/or porphyry mineralisation. The company said that the hot rhyolite (volcanic) dome of Alteration Ridge is east of the SW Corner.
The company noted that none of the 20 samples contained reportable grades of metals. Inca said that the geochemical signature nevertheless confirmed the upper and/or lateral position of SW Corner in relation to the intrusive system.
The company said that the targets below RP28 and RP29 remain prospective as they remain untested by this brief mapping and sampling program.
Inca said that the identification of the alteration assemblage in the SW Corner is important as it can be useful in vectoring heat flow and therefore centres of mineralisation related to epithermal and/or porphyry intrusive systems. The company concluded that the SW Corner of Riqueza is towards the margins of the large intrusive related mineralised system known to occur at Riqueza. This is consistent with that anticipated in terms of the overall system at Riqueza.