Bramaderos was sporadically explored during the periods 1970 to 1984, 2001 to 2002 and 2004 to 2007. During this period the property has been known as Rio Playas and subsequently Curiplaya.
United Nations Development Project
Rio Playas was discovered in 1970 during a regional systematic geochemical survey conducted by a United Nations Development Program (UNDP) in conjunction with the Spanish Aid mission. This work showed that several southeast-flowing and northwest-flowing tributaries of the Playas River were anomalous in copper, molybdenum, lead and zinc.
Between 2001 and 2002 Ecuanor S.A. – an Ecuador-based junior mineral exporation company - undertook a range of exploration activities at Curiplaya including geological mapping, stream sediment surveys and soil surveys, rockchip sampling, ground magnetic surveys, electrical geophysical IP surveys and drilling of 13 diamond drill holes for a total meterage of 3252m.
Ascendant Gold S.A.
In 2004 Ascendant Gold S.A. optioned the Curiplaya property, but subsequently completed very little work at Curiplaya beyond re-interpretation of existing data collected by Ecuanor and the collection of 17 surface grab samples from the Bramaderos, Melonal and Porotillo zones.
Ecuador Gold S.A.
In September 2006 Ecuador Gold acquired all of Ascendant’s right, title and interest in the Curiplaya and Curiplaya 1 concessions and over two years undertook geological mapping, grid soil sampling, trenching and associated channel sampling, geochemical and geophysical surveys and drilling of 22 diamond drill holes for a total meterage of 7174 metres. Exploration activity ceased in April 2008 when the Ecuador Constituent Assembly passed a Mining Mandate which, amongst other provisions, provided for the suspension of exploration activities for 180 business days, or until a new Mining Law is acted.
The outcome of the various phases of exploration activity conducted on the Curiplaya property between 1970 and 2012 was the identification of several centres of porphyry style gold-copper mineralization that were associated with quartz vein stockworks and breccias hosted by a cluster of potassic-altered, northeast-aligned, quartz-diorite porphyries that exhibited typical porphyry alteration and mineralization patterns at the Bramaderos, Porotillo and Limon prospects and elsewhere. In addition, breccia-hosted epithermal mineralization was also identified on the property at West Zone.
An extensive, 5km by 1-2km, gold and copper (+/- molybdenum) soil geochemical anomaly was located in the central part of the property by historical exploration and has been only partially tested by trenching and diamond drilling, with several zones remaining to be followed up. During this historical period a total of 888 rock and 1324 soil samples were collected, 17 trenches excavated and channel sampled, 31 line kilometers of magnetic and Induced Polarization (IP) surveys carried out and a total of 10,426m of diamond drilling performed to test some of the anomalous areas.
Historical results from drilling at Bramaderos produced wide mineralized intervals such as 260m at 0.6g/t Au and 0.14% Cu. Trenching at the West Zone breccia produced results of up to 42m at 3.7g/t Au. (A.C.A. Howe NI 43-101 Report, 31 August 2006). These results, together with the distribution of alteration, indicate that Bramaderos is a fertile mineralized porphyry system, with significant discovery potential for both porphyry Au-Cu and epithermal Au systems.
Cornerstone Capital Resources and Sunstone Metals
On January 5, 2017, Cornerstone announced that its subsidiary, La Plata Minerales S.A. ("Plamin"), had been awarded the "Bramaderos" concession in Ecuador following a public bidding process. On 10 April 2017 Cornerstone announced that Plamin had signed a binding letter of intent with Avalon Minerals Ltd (Sunstone Metals).