Oso Blanco Property, Sonora State, Mexico

Oso Blanca - View looking NE to the Huerigo Zone (in the valley) on the Oso Blanco 2 mining concessionOverview:

NSX Silver holds a 100% interest in three contiguous mining concessions (Oso Blanco, Oso Blanco 2 and Piedras del Norte) comprising approximately 5,600 hectares of prospective ground located in Sonora State, Mexico.  These concessions are situated in the Sierra Madre Occidental (“SMO”) in a cretaceous volcanic suite, which is regionally denoted as the “Lower Volcanic Sequence”.  These rocks are overlain and completely covered to the East by a tertiary sequence of rhyolite tuffs and basalts regionally known as the “Upper Volcanic Sequence”.  The interface between these sequences, and in particular the upper parts of the Lower Volcanic Sequence, is the host environment for several significant gold and silver districts including the nearby Sahuaripa, Mulatos, Dolores and Ocampo Districts and further south the El Sauzal discovery.  The geologic setting of these deposits varies but they all occur at or within this highly prospective interface.

Geochemical sampling and mapping at the Huerigo area, located in the western portion of the Oso Blanco 2 mining concession, has identified an 8 km2 area of highly prospective ground.  Anomalous zones were defined by elevated silver-lead-copper assay values supported by multi-element assay values that exceed the statistical background populations.  Background levels for silver, lead, and copper are 1.3, 18, and 20 ppm respectively. The main Huerigo metal anomaly occurs as an arcuate 900X300 meter multi-point silver anomaly, supported by coincident anomalous lead and copper values.  Silver values range from background to a maximum of 545 grams per tonne, with lead values reaching 2.05%  and copper reaching 2.1%  Of the total 941 samples tested, an impressive 302 samples (32%) contained anomalous silver, copper, and lead. Several historic mine workings have been located on the Oso Blanco 2 concession.

To date a total of five anomalous zones have been identified in the Huerigo area.  Recent efforts focussed on two of these zones; the Los Tajos Zone to the south and the Chipahuiri Zone to the north.  These zones are located approximately 5 kilometers apart and both have had only limited exploration conducted in the past. Highlight results from the 2013 exploration program are listed below;

Los Tajos Zone: 

  • 3.41 grams per tonne gold and 95 grams per tonne silver and in a 2 meter trench
  • 189 grams per tonne silver and 0.174 grams per tonne of gold in a 2 meter trench
  • 141 grams per tonne of silver in a 2 meter trench

Chipahuiri Zone:

  • 42.2 grams per tonne silver over a continuous channel of 14 meters in close proximity to an old mine working; including one sample grading 190 grams per tonne silver and 0.284 grams per tonne gold and a second sample grading 33.5 grams silver and 0.347 grams gold, each over 2 meters

Detailed mapping and geochemical sampling on the Oso Blanco 1 and Piedras del Norte concessions has also yielded encouraging resulting results at the Santa Rosalita and La Prieta zones.  The Santa Rosalita Zone is a newly discovered mineralized zone located immediately north of the town of Santa Rosa. Mineralization in this zone occurs in a shear zone of indeterminate size that is obscured by heavy overburden in an area with difficult access due to dense vegetation.  Significant values obtained during initial sampling in this zone included one sample returning 2,030 grams per tonne silver, 1.26% lead, 0.31% copper and 0.14% zinc. At the La Prieta zone NSX Silver has identified a 700 meter long narrow shear zone, approximately 0.5 to 1.2 meters in width, that hosted the old La Prieta polymetallic mine (copper, lead, zinc, gold, and silver). A substantial dual compartment inclined shaft was found during prospecting.  Testing and trenching along this zone indicates that high values of silver and gold occur along much of its length. Of the 41 samples taken along the strike of the shear, 31samples (76%) exceeded the assigned background silver value of 5 grams per tonne. Anomalous assays along the length of the zone range from trace to a high value of 352 grams per tonne silver and from trace to a high value of 9.4 grams per tonne gold.  Of note is the fact that most of the higher grade silver samples also returned significant gold values.

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