La Frontera

The La Frontera property is a low sulphidation epithermal style silver-gold prospect located in Catamarca Province, Argentina, 320 km west southwest of the City of Salta. The property is owned 100% by Aldebaran. Access is by 75 km of rough 4 x 4 or quad trail from the south end of the Salar Rio Grande.

Geology and Mineralization

The area of the project displays a relatively flat topography, characterized by a vast north-south central valley surrounded by low elevation rounded hills with outcrops of welded volcaniclastic rocks and minor felsic intrusive units. The topographically depressed central portion of the project is mostly covered displaying suboutcrops of volcaniclastic rocks and minor felsic and also mafic intrusives.

There is an occurrence of widespread low sulphidation (quartz-adularia) epithermal type within Tertiary felsic volcanics. Multiple areas show well-developed quartz stockwork with associated Au-Ag mineralization and presence of Pb-Zn-Cu. The majority of limited outcrops are mineralized and the area is mostly covered by thin colluvium. Areas of exposed and inferred mineralization cover an area exceeding 1,500 m in length.

In addition, sampling at the Amethyst zone located one km northwest of the main mineralized trend has returned erratic yet significant values of gold and silver. In excess of 80 samples were assayed with values ranging from nil to 4.3 g/tonne Au and from nil to 43 g/tonne Ag. The Amethyst zone comprises an area of intense stockwork and sheeted quartz-adularia veining which measures 250 m by 300 m. Geological elements suggest the Amethyst zone may represent a low-grade silica cap above higher grade mineralization at depth.

Exploration History

2000: Mineralization at the La Frontera property was initially discovered and staked by Mansfield’s exploration team in March 2000. There was no evidence of previous exploration in the area.

2005-2007: Under a 2005 joint venture agreement with Mansfield, Apex Silver Mines Ltd completed 1,960 m of trenches (Table 1), sampling, 17 km of electromagnetic geophysical survey in 9 lines, and built approximately 160 km of access road to the project. In 2006, a drilling program of 2,149 m in 12 drill holes was completed. This limited drilling encountered mineralization at depth (Table 2), but favorable structures and zones were not likely properly tested. There is potential for mineralized corridors with multiple orientations and strike-lengths in excess of 1 km. Apex dropped the property in 2007.

2008: The La Frontera property was transferred to Pachamama as part of a restructuring of Mansfield.

2012: The property was transferred to Regulus as part of the merger with Pachamama.

2018: The La Frontera project, together with Rio Grande, Aguas Calientes and other early stage Argentina projects, was spun out into Aldebaran.

2019-Present: No work is currently planned for this project in the Aldebaran portfolio; however, the Company is evaluating and planning how to move the project forward. In parallel, the Company has been engaged with third parties to discuss potential for joint venture or other partnerships to advance the project.


Trench Width Au
North Trench 6.2 m 0.60 2344.0 71.00
Trench II 38.0 m
incl. 10.0 m
Trench VIb 24.0 m 0.60 18.0 6.30
Trench V1a 6.0 m
and 2.0 m
207.0 0.54
Breccia Sur 14.0 m
incl. 2.0 m
3.23 71.0

Table 1: Highlights of 2005 La Frontera Property Trenching Results

Hole From (m) To (m) Width (m) Au ppm Ag ppm


153 171 18 0,59 34,33
including 163 164 1 1,16 83,00
167 171 4 1,63 385,50


91 93 2 0,85 3,50


48 53 5 0,99 52,60

Table 2. Significant results from the 2006 drilling campaign

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