Property Status
- Property History
The following description of the exploration history of the Rio Grande property is modified after Armbrust et al. (2005); who in turn drew heavily on a report by Kesting (2002).
In June and July 1999, Mansfield Minerals Inc prospected the Rio Grande area collecting 210 surface rock samples which defined and delineated a zone of copper-gold mineralization. A simplified sketch alteration map was generated showing the different alteration types and exploration targets in the 2- by 2-kilometer area.
In early 2000, Mansfield signed a joint venture agreement with Minera Teck de Argentina, a wholly owned subsidiary of Teck. Teck had the opportunity to earn a 55% interest and was the manager of the exploration project.
During April and May 2000, Teck prepared a geological map at a scale of 1: 20,000, covering roughly an area of 80 square kilometres. A smaller zone, mainly consisting of the area of potassic and scapolite-diopside-magnetite alteration, was mapped at a scale of 1: 5,000. Another 118 surface rock samples were collected which defined additional new mineralized zones. An orientation soil survey was completed in an attempt to test the usefulness of soil geochemistry in detecting the newly discovered mineralization. Three hand trenches were dug and channel samples collected along their length; these assays returned encouraging results.
Follow-up exploration programs restarted in September 2001. The soil survey was completed over an area of 20 square kilometres, with some 1,420 samples collected; the results showed an extended gold-copper anomaly.
Quantec Argentina performed geophysical surveys consisting of ground magnetics covering an area of 12 square kilometres, and an Induced Polarization (IP) survey covering an area of 3.5 square kilometres. A 2.7-kilometer trenching program was undertaken in order to test the Cu-Au anomalies generated by the soil sampling and prospecting programs. In all, 22 trenches were completed in the main area, as well as 5 test pits.
Special studies were performed to better understand the alteration and mineralization styles; including petrography studies, K-Ar geochronology and Pima studies. A diamond drilling program consisting of 11 holes, totalling 3,220.6 meters was completed. The detailed results of Teck's exploration programs are described in reports Smith (2000) and Smith (2001). Additional work on the property was recommended; however, Teck terminated its exploration efforts in Argentina in early 2002, and returned the property to Mansfield Minerals Inc.
In October 2002, Mansfield Minerals Inc. designed a program to re-map the Rio Grande property and re-interpret all exploration results previously generated. Ten days were spent in the field remapping, at a scale of 1:5,000, the lithology, mineralization, and alteration in the central mineralized portion of the Rio Grande property; an area of 10.5 square kilometres. Outcrops, trenches, road cuts and information generated by drilling were use to complete the mapping. Core was re-logged, and reinterpretation of the geophysics was completed.
In June 2004, Mansfield Minerals Inc. and Planet Ventures Inc. (predecessor of Antares) signed a joint venture agreement in which Antares Minerals Inc., via its Argentine subsidiary Minera Antares Argentina S.A., became the operator for exploration on the property. Antares began actively exploring the property in October 2004 and completed the first phase of this work in May 2005. A second phase of drilling commenced in early 2006.
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