The El Torno Gold Project is centered on a past-producing gold mine located in the Andean Cordillera in the mining friendly province of Jujuy , Argentina near the international border with Bolivia.
The property consists of four mining rights covering a total of 7,863 hectares. Soltera has a rental/purchase agreement with the titleholder. The area is accessible by road all year round, with electricity available from Santa Catalina Village (8 km away) and abundant water in a nearby river.
El Torno contains a large gold-rich quartz vein system that extends north-south for 14 km and is up to 2000 meters wide. The central parts of the system have been worked since the Incas, resulting in about 1 km of underground galleries that are now flooded or collapsed.
The vein system was investigated by Puma Minerals in 1997 who carried out over 2,100 m of drilling. They were followed in 1999 by Peñoles (discoverer of the world’s largest silver mine and Mexico’s largest and richest gold mines) who undertook trenching, grab sampling, and geological surveying as well as a geophysical IP survey. The drilling showed that gold is concentrated in a 2 metre-wide zone on the western side of the main vein. Puma estimated that a 1.3 km length of the vein could have the potential for over 500,000 ounces of gold to a depth of 100 metres or 2 million ounces to a depth of 400 metres at an assumed grade of 10 g/t gold (not NI-43-101 compliant).
In 2008-2009, two stream sediment geochemical sampling programs covering the whole license area and a detailed structural survey were carried out. The results showed that:
- The main vein system appears mineralized along its full length of 14 kilometers.
- The vein system is folded into an anticline. The mineralization tested by Puma drilling in the west wing could extend into the east wing, which remains totally untested.
- There are broad and strong stream sediment geochemical gold anomalies over wide areas of the country rocks up to 2 km from the main vein that are centered on suites of small veins and stockworks that could be major open-pit targets.
- The exploration area was reduced from 78 km2 to 28 km2 within which there is potential for several million ounces of both underground and open-pit gold.
In 2011-2012, the company concentrated on an extensive program of geological mapping and surface sampling that included more than 470 trenches and 11,000 gold analyses, together with a targeted geophysical EM-IP survey. The results included:
- There is a zone of pervasive mineralization that extends north-south throughout the whole central area.
- Within this broad zone, there are significant gold concentrations. A total of 541 samples contained more than 0.4 g/t gold, which is a potentially reasonable economic cut-of for open-pit operations and, of those, 285 contained more than 1 g/t.
- A selection of analyses with more than 5 g/t gold are shown below; all are 1 meter-long chip-channel samples:
|5.81 g/t||6.01 g/t||7.93 g/t||5.22 g/t||11.05 g/t|
|166.5 g/t||9.73 g/t||7.51 g/t||7.26 g/t||64.2 g/t|
|8.75 g/t||6.29 g/t||21.4 g/t||9.47 g/t||5.18 g/t|
- Six highly prospective target areas were defined for further test work.
We now have considerable data about gold on the surface, but very little about it at depth. Old workings and the 1990’s drill holes show that gold occurs to at least 100 meters below surface, but drilling is absolutely essential to ascertain its quantity and distribution. A drill program is being planned.
The figure below shows the distribution of the 541 bedrock sample analyses containing more than 0.4 g/t gold which is a possible cutoff level for future open-pit mining. All the samples represent channels at least 1 m in length cut along the sides of trenches. These gold analyses indicate six target areas for further test work, five of which cover parts of the main vein system and one is about 1 km to the west.
Furthermore, the surface trenching program outlined above produced some spectacular results, including a 1.5 m channel sample containing 376 gpt Au. and this raises the possibility that small-scale production may be possible from ‘hot spots’ in the area; this possibility will also being investigated.
Argentina is rapidly becoming one of Latin America’s major copper and gold producers, posting a remarkable increase in production over the past 3 years. Gold, copper and silver production is set to increase with Argentina historically being a major producer of industrial minerals and construction materials which contributed at least 66% of mining earnings, while metalliferous minerals contributed only 24%. Read More…