Highlander Silver Provides Update on La Estrella Geological Model and Drilling Plans - Seite 3

Hydrothermal alteration is mostly hosted within the early facies of the dome complex, with a large silicified core surrounded by strong quartz-sericite alteration and an outer halo of weaker illite-kaolinite or chlorite alteration (Fig. 4). Hydrothermal alteration is pervasive affecting the vitreous-rich early dome facies, and follows upflow channels through a set of North-South and Northeast structures (Fig. 5).

The mineralisation is found in disseminated and vein forms, associated with silicification and quartz-sericite alteration.

There are 2 stages of mineralisation: 1. Early stage and 2. Epithermal stage (Fig. 6).

1. Early stage: Related to a late-stage magmatic derived, high temperature hydrothermal fluid, introduced into the dome complex shortly after emplacement, forming a large footprint of ~2,000 m x 600 m controlled by NE and N-S structures. Mineralisation of Au±Cu±As is associated with medium-coarse pyrite, within veinlets, disseminated, cementing hydrothermal breccias or as quartz vein halos.

2. Epithermal stage: Later than the Early stage, consists mainly of quartz with fine-grained dark sulphides (pyrite-Ag sulphosalts and scarce galena and chalcopyrite) with polymetallic mineralisation of Ag±Au-Pb>Cu>Zn. The epithermal stage is commonly emplaced in discontinuous and thin structures, and as diffuse halos around early stage pyrite, mainly related to NE upflow structures.

Foto: Accesswire

Fig. 4. Map showing the widespread distribution of hydrothermal alteration, which forms a large zone of about 2,000 m x 500 m with a silicified core surrounded by quartz-sericite alteration.

Foto: Accesswire

Fig. 5. a. Silicified (quartz+pyrite) and mineralised ridge (1) with halos of quartz-sericite alteration (2), which is part of a large set of prospective Northeast structures at the central block of the dome complex. b. Detailed of upflow channel formed by hydrothermal breccia cemented by fine-grained black sulphides and quartz (1) hosted by early dome facies with quartz-sericite alteration (2).

Foto: Accesswire

Fig. 6. Core photos from Early stage and Epithermal stage mineralisation.

1. Early stage mineralisation:

a. Fine-grained porphyritic dacite with veinlets, irregular open space filling and disseminations. DDH-E26: 177 m, 2.49 g/t Au, 13 g/t Ag.

b. Amygdale - rich andesite, mineralisation in irregular quartz veinlets and amygdale filling with pyritic halos. DDH-E24: 128 m, 0.79 g/t Au, 4 g/t Ag.

2. Epithermal stage mineralisation: