During years 2004-2006 Antares (predecessor of Regulus) had a JV agreement with Mansfield to conduct exploration in Catua. The main activities in that period at the project site were:
- Reconnaissance, geological mapping, geochemical sampling, and prospecting,
- 54 line kilometre Induced Polarization/Resistivity geophysical survey at 100 m and 300 m dipoles.
- Line kilometre gravimetry survey, with the aim to identify the depth of the basement.
- 1378.65 meters in 8 drill holes with both, RC and DDH methods.
The geological reconnaissance program consisted of identifying and mapping the main geological units present in Catua property onto a Quick Bird image at a 1:10.000 scale. The purpose of this mapping was to enhance our understanding of the geological setting of the known copper mineralization, look for possible extensions, and to establish possible genetic models and potential for the copper mineralization.
The aim of the Induced Polarization/Resistivity geophysical survey was to try to locate the source of exotic copper that occurs near the centre of the surveyed area. Resistivity measurements for both configurations were low while chargeability measurements were low to at best moderate. The 100m dipole survey was designed to test for a source or ‘feeder’ below the occurrence. While results show a weak anomaly slightly offset from the copper, there is no clear evidence for a ‘feeder’ zone or structure below the occurrence. 3D inversion of the data indicates that the known copper occurrences are at least spatially related to zones of lower chargeability within an implied chargeable ‘ridge’. The 300m dipole survey was designed to try to locate potential distal sources for the copper. While no clear target areas were defined, several areas were identified with elevated chargeability at depth that could represent unoxidized sulphides and a potential source for the known exotic copper oxide mineralization.
Gravity data were collected along two lines approximately 5 km long. The aim was to identify the depth of the basement, which is outcropping to the eastern boundary of the tenement. According to the obtained results, some possibilities have been interpreted: Different interpretations, assuming different ground density values, show the possibility of a concealed intrusive below the gravels or ignimbrites in a graven structure of the basement. Other models are less consistent, but the drill holes did not confirm the models.
Drilling done by Antares (predecessor of Regulus) consisted in 8 drill holes for a total of 1378.65 meters with both, RC and DDH methods (Figure 2). Drill holes did not find additional mineralization, or areas with alteration of interest.
Figure 2: Location of drill hole collars and detail of mining claim for the Catua project.