Promising announcements from three junior miners and explorers on projects in Santa Cruz province highlight the continuing potential for gold and silver mining in Patagonia
New announcements from Samco Mining, Minera IRL and Mariana Resources, relating to separate exploration projects confirm the continuing high prospectivity for high grade gold and silver in the Deseado Massif in Patagonia in Argentina's Santa Cruz province.
Samco's announcement relates to its Corina project area which lies immediately to the north of the exciting Cerro Moro vein deposits found by Extorre Gold - and recently acquired by Yamana Gold. Here an initial program of mapping and chip and channel sampling following up on targets identified in a previous satellite imagery analysis has confirmed a number of exciting targets, which the company refers to as the Cerro Cubilete and Cerro de la Mina prospects.
At the former, an area of outcrop of dark quartz and quartz-iron oxide breccia has been identified over a north-south elongated area measuring approximately 250m long by up to 90m wide. Within this area, 44 outcrop samples averaged 268 g/t Ag, with a maximum value of 1295 g/t Ag. While not reported, the vein deposits in this area also tend to carry gold values as well as silver.
At Cerro de la Mina approximately 600 metres NW of Cerro Cubilete there are many small prospecting pits which expose minor barite and Mn oxide mineralization in rhyolite. Seven samples from this area assayed above 50 ppm Mo, with a maximum of 219 ppm, in a NNW linear trend 300m long. In Samco´s experience, Mo can be a useful pathfinder to precious metal mineralization in this environment - indeed the major operating gold/silver producer in the area, Anglo American's Cerro Vanguardia mine, was originally found by geologists looking for barite deposits.
The project is located some 55km for the port of Puerto Deseado and there is good road and power infrastructure in the area.
Meanwhile another miner/explorer with more advanced projects in the area, Minera IRL, has reported the discovery of a significant mineralized system at Choique, approximately one kilometre from the Martinetas Vein Field, at the Don Nicolas Project in the same general area. Don Nicolas is currently in the development permitting process and is located about 100 km northwest of Cerro Moro.
Here results from 35 holes for 2,386 meters of drilling have demonstrated substantial gold and silver intersections in a new mineralized rhyolite dome host within 50 metres of surface. Key high grade intersections include drill holes CH-D12-015 with 6.70 meters at 10.5 g/t gold and 19.8 g/t silver, CH-D12-018 with 6.10 meters at 5.43 g/t gold and 27.6 g/t silver and CH-D12-021 with 11.10 meters grading 5.38 g/t gold and 5.26 g/t silver. This is particularly significant as Choique is located only 1.6 kilometres from the planned Don Nicolas treatment plant.
Courtney Chamberlain, Executive Chairman of Minera IRL, commented, "The strong assay results from a newly recognized rhyolite dome complex at Choique unlock significant value close to the main mineralized vein system at Martinetas and represent a positive return from our recent brownfields program. Only 1.6 kilometres from the planned Don Nicolas plant, the Choique discovery not only shows immediate potential for increasing the resource base and mine life, but also provides great encouragement for more potential discoveries close to Martinetas."
A Feasibility Study for building a mine at Don Nicolas was completed in February this year. The Environmental Impact Assessment (EIA) was submitted to the Santa Cruz authorities in, thereby commencing the process of obtaining the development and operating permits for the project. In addition to the drilling at Choique, 15,905 meters of in-fill and extension drilling have now been completed at Martinetas, both of which will provide the basis for a new resource estimate scheduled for the fourth quarter of 2012.
Some 30+ km from the Don Nicolas project lies Mariana's Las Calandrias and Calandria Sur prospects where there has also been extensive, and highly encouraging, drilling, both on high grade silver/gold veins and around the edges of a rhyolite dome, which also extends into ground controlled by Minera IRL (known as the Escondida project), and which has shown lower grade bulk gold mining potential. Mariana too has just announced results from twenty-one holes drilled for 2,164m including deepening six previous holes, designed to test new targets adjacent to the current Calandria Sur resource of 519,000 ounces gold equivalent and to validate geological models derived from detailed exploration.
The company reports significant intersections made in 13 holes - mostly hosted by volcaniclastic or volcaniclastic/rhyolite rocks and these range in style from bulk tonnage, narrow high grade (in one case, andesite dyke-related) to wide zones of strongly anomalous gold.
Relating to the latest drilling results, Mariana's chairman, Chairman John Horsburgh noted, "This is a good set of results from several new targets, all of which are outside the Calandria Sur resource of 519,000 ounces of gold equivalent. Post-resource drilling to date has assessed the extent of the Calandria Sur mineralised system. Importantly mineralisation at Loma Verde, La Picaza and El Clavo is still open and adjacent covered areas, possible sub-dome feeders, the 1km dyke trend at Calandria Sur and several advanced targets within a 3km radius also remain as targets. Meanwhile,
follow-up exploration is underway in the extensive Bozal/Tongoril areas to the north and northwest with new targets emerging, for which we look forward to updating in due course."
The three announcements, which all came within a day of each other, confirm the high prospectivity for gold and silver in the region, which, as noted above already hosts one significant gold/silver mine in Cerro Vanguardia with a couple of others at the development stage and a host of significant finds, some of which, like Don Nicolas and Cerro Moro are well on the path to production. The Deseado Massif has to be one of the world's most prospective areas for gold and silver and the provincial government of Santa Cruz province, unlike some of its neighbours, has so far proved to be a very mining friendly administration although there are reports that the province is considering the imposition of new mining royalties and forcing miners to cede a 10% stake in projects to the state mining company, Formicruz, in an effort to to bring down its budget deficit.