Gold and Silver mineralization at the Nico project was first discovered by Mirasol geologists in 2004 while following up high priority targets from the company’s Santa Cruz generative program. Mirasol completed a surface exploration program at Nico comprising geological mapping, rock chip sampling, ground magnetics and electrical geophysics, defining a series of drill targets at the Nico Main Prospect. In February 2009, Mirasol joint ventured Nico to Coeur Mining (Coeur) who were at the time operating the bonanza grade Martha Silver-Gold mine in the area. Coeur completed one program of drilling returned the project to Mirasol without any retained interest. Mirasol kept Nico on “care and maintenance” until the recent changes in the Argentine investment climate encouraged Mirasol to recommence exploration late in 2016. From November 2016 to date, Mirasol staked additional new claims at Nico to cover potential extensions of the mineral trends, bringing the total area covered by the Nico project to 73,000 ha.
The Nico Project is situated in a logistically favorable setting in rolling hills at a modest elevation of approximately 600 m AMSL. The project is traversed by a well-maintained provincial gravel road. Nico is located 43 road km north of the historic Martha high grade silver mine, recently recommissioned by Hunt Mining, and 83 road km northwest of the Manantial Espejo Silver-Gold mine operated by Pan American Silver.
In 2009, the Nico project was under Joint Venture with Coeur. During this time, Coeur completed one drilling program totalling 1,472 m in 11 shallow holes at Nico Main with best results of 8.25 m @ 0.43 g/t Au and 37 g/t Ag, including 1.25 m at 2.17 g/t Au and 197 g/t Ag. No follow-up drilling was undertaken and the project was returned to Mirasol.
In 2016, encouraged by an improving investment climate, Mirasol resumed activity at the project. To date, Mirasol has identified three prospects Aurora, Resolution and Nico Main where strongly anomalous to bonanza grade silver–gold assays have been returned from surface rock chip sampling and historic drill intersections at the Nico Project.
The geological understanding emerging from the 2016/2017 exploration programs at the Nico Project suggests that mineralization is associated with a large rhyolitic flow dome and pyroclastic complex that overlies the regional rhyolite ignimbrites volcanics of the Chon Aike formation. The Nico project is now known to contain, three strike extensive Au+Ag vein prospects at Resolution, Vittoria and Aurora and mineralization known from a previous round of drilling at the Endeavor prospect. Resolution, Vittoria and Aurora are new prospects with no previous drilling that contain mineralized vein trends ranging from 1.2 to 4.0 km in length with wide-spread anomalous to bonanza-grade Au+Ag rock chip assays of up to 35 g/t Au and 6,181 g/t Ag from surface sampling.
Mirasol interprets the Nico mineralization to be an example of Ag-rich epithermal intermediate sulfidation system. This class of mineralization has produced a number of high-grade Au+Ag vein and bulk-mineable ore bodies in Santa Cruz Province, including the Yamana’s Cerro Morro and the Hochschilds / McEwen mining’s San Jose mines.
The two phases of mapping and sampling completed at the Aurora Prospect have defined a principal north-south oriented mineralized trend of approximately 4 km. A total of 1,113 rock-chip samples have been collected to-date and with assays ranging up to 35.09 g/t Au (1.128 oz/t) and up to 2095 g/t Ag (67.4 oz/t). The database of sample assays for Aurora contains:
178 samples greater than 1 g/t Au (0.032 oz/t)
34 samples greater than 5 g/t Au (0.161 oz/t)
6 samples greater than 15 g/t Au (0.482 oz/t)
155 sample greater than 60 g/t Ag (1.9 oz/t)
41 samples greater than 300 g/t Ag (9.6 oz/t)
5 samples greater than 900 g/t Ag (28.9 oz/t)
Field observations and assays distribution suggest the presence of multiple mineralised vein-breccia zones (potential shoots) that are expressed as a linear alignment of intermittently outcrop, subcrop and float of blocks, defining vein-breccia trends over a 4 x 2.1 km area at the prospect. This trend extends to the edge of post-mineral basalt cover to the north and south, suggesting the system may continue under cover and have a longer strike length than currently defined. As well, outcrop and sub-crop distribution of samples suggests the potential for adjacent parallel vein breccia trends in some areas of the prospect. Sample widths at surface show individual vein-breccias typically range between 0.2 to 3.0 m in width with an average of 0.31 m.
Reconnaissance mapping and sampling has led to the discovery of a new high-grade epithermal vein at the Resolution Prospect. The mineralization reports to oxidized veins and veinlets of grey chalcedonic silica with localized zones of banded saccharoidal silica and breccia textures hosted in dacitic subvolcanic. As currently defined by anomalous Au+Ag rock chip assays, the Resolution Trend is a 1.25 Km long zone, defined by parallel 0.1 to 1.0 m wide veins and intervening stockwork veinlets, that combine to from up to 80 m wide zones of veining and stockwork. The Resolution Trend represents an attractive drill target for bulk mineable gold+silver mineralization.
Mirasol has collected 115 reconnaissance rock chip samples along the Resolution vein structure. Assays returned high grade Ag+Au with strongly anomalous As+Sb+Hg+Pb+Zn. The database of sample assays for Resolution contains:
45 samples greater than 30 g/t Ag (0.96 oz/t)
10 samples greater than 300 g/t Ag (9.6 oz/t)
Highest sample of 6,181.4 g/t Ag (198.7 oz/t)
28 samples greater than 0.25 g/t Au (0.008 oz/t)
15 samples greater than 1.0 g/t Au (0.032 oz/t)
Highest sample of 5.73 g/t Au (0.18 oz/t)
Vittoria Vein Trend
Recent reconnaissance exploration at Nico has also identified an additional new Au+Ag prospect, the Vittoria Vein Trend, that to date has been traced over a 1.6 km strike length.
The Vittoria Vein Trend as known to date, ranges from sub-meter to locally up to 10 m wide trend, characterized by multiple parallel 0.3-0.5m wide chalcedonic quartz vein outcrops and sub-cropping blocks, that have returned rock chip assays of up to 1.44 g/t Au and 174 g/t Ag.
The company anticipates the next stage of exploration at the Nico project will include geological mapping, systematic rock chip sampling, and electrical geophysical surveys. Results from this exploration program will be used to drive integrated analysis for drill target selection and potential drill testing during the Southern Hemisphere summer 2018 season.
To learn more about past and recent results and the exploration potential at Nico, see all Current and Historical News Releases below.