Alien Metals possesses almost 1,500 hectares of mineral concessions within central Zacatecas, Mexico, which includes brownfield sites and past-producing mines. These mineral concessions have been reviewed by Alien Metals' geologists and a low cost work programme to advance targeted exploration is underway.

Los Campos Property

The Los Campos project covers approximately 500 hectares and is located in the southern part of the Zacatecas District, a world-class epithermal silver-gold district that has historic production in excess of 1 billion ounces of silver and nearly 10 million ounces of gold. The Los Campos was reportedly an important producer of silver in colonial times, and surface workings consist of four vertical shafts of unknown depth. In the centre of the project is an inactive kaolin quarry.

The geology of the Los Campos concession consists of intermediate volcanic rocks overlain by rhyolite, rhyolite tuff and red conglomerates. Very little is known about mineralisation on the Los Campos property. What is visible on the dumps appears to be epithermal in nature and similar to mineralisation elsewhere in the Zacatecas district. The prominent 200m x 100m illite-smectite hydrothermal alteration pipe is thought to be the barren clay alteration cap that has formed above an epithermal silver-gold deposit.

In the south of the prospect outcrops rocks of the Eocene conglomerate that could be a favourable host for quartz stockwork veining and disseminated silver-gold mineralisation, similar to that found at the Laguna Zacatecana prospect east of Zacatecas.

Ten samples were taken by the Mexican government in the 1980’s from the two dumps associated with the main shafts. These dumps were estimated to contain 9,000 tonnes averaging 134 g/t Ag. Similar data is available for the San Vincente dumps, which were estimated to contain 27,681 tonne averaging 123 g/t Ag.
Figure 1 Los Campos concession map

Figure 1 Los Campos conce…
Figure 2 Los Campos

Figure 2 Los Campos
Figure 3 Los Campos

Figure 3 Los Campos

Ojocaliente Properties

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.
Figure 4 Las Cristinitas Vein

Figure 4 Las Cristinitas …
Figure 5 Las Cristinitas Vein

Figure 5 Las Cristinitas …
Figure 6 Las Cristinitas Vein

Figure 6 Las Cristinitas …

Other properties in the Ojocaliente area include:

  • La Africana and Ampliacion El Cabezon
    • 2 small concessions covering a high grade epithermal vein. Arian has conducted underground geological mapping and sampling of 2 narrow, high grade silver veins that have returned values of up to 1195 g/t Ag, 0.55 g/t Au, 0.98% Zn, 0.6% Pb, and 0.04% Cu.
  • Donavan 1
    • The Donovan 1 prospect covers a number of wollastonite tungsten quarries with minor copper oxides suggesting that they may be related to a volcanic-hosted massive sulphide deposit.
  • Donavan 2
The Donovan 2 concession covers a number of prospects that have minor copper oxides on fractures in dump material. Surface mapping identified numerous areas with silicified, iron stained andesites that could represent exhalites peripheral to a Volcanic massive sulphide deposit similar to San Nicolas (Teck - 80Mt @ 1.6% Cu) found 24km to the NE.
Figure 7 Donavon 2 concession map

Figure 7 Donavon 2 conces…
Figure 8 San Celso, Donovan 1 and Africana Properties

Figure 8 San Celso, Donov…
Figure 9 Donovan 2 panorama view

Figure 9 Donovan 2 panora…