Alien Metals has several concessions in the south of Zacatecas near the towns of Ojocaliente and General Pánfilo Nateras. Access to these properties is by paved road to nearby villages and then unimproved dirt roads to the respective properties. All properties are within 50 kilometres of Zacatecas.
Rocks exposed in the area range in the age from Triassic to recent. The area consists of a large north-west trending anticlinal structure and an intermediate intrusive exposed in the core. The unit intrudes schist, limestone and marl, which are all overlain by Tertiary andesites. All of these units are partially, or in some cases wholly covered by Tertiary rhyolitic volcanics. Felsic porphyries cut the sediments, the batholith and the andesites.
There are two mineralising events in the Ojocaliente area. The oldest is related to the Pánfilo Nateras batholith and consist of Ag, Pb, Zn and Cu replacement mineralisation in the limestones. The younger mineralisation type occurs as epithermal veins in both sedimentary and intrusive rocks.
The precise date of the discovery of the first mines in the area is not known but is thought to be around 1600. Many of the veins in the area produced from near surface oxidized material and some of the silica rich material was reportedly used as smelter flux.
San Celso Property
The San Celso property covers a number of colonial era mines that have mined a number of veins to a depth of approximately 100 metres, which is the depth of the local water table. Each of the accessible mines has numerous stopes indicating the presence of high grade shoots within the San Celso and Las Cristinitas veins.
Mineralisation occurs as low sulphidation epithermal veins. The vein thicknesses range from 0.5 to 4.5m. There are two principal veins – the San Celso and Las Cristinitas veins they are both approximately one to five metres wide. Arian has completed underground mapping and sampling of both veins that suggest high grade silver mineralisation continues beneath and along strike from the historic workings.
Project scale mapping and sampling has discovered several unexploited veins that have returned grades in excess of 100 g/t Ag with minor gold and base metal credits that suggest that additional silver-bearing structures exist.