On a district scale, the gold potential of the Guiana Shield is vast, but remains untapped. The Guiana Shield is analogous to the West African Shield, with which it shares a common geologic history. More than 30 gold deposits have been discovered in the West African Craton, which has undergone systematic surface exploration over the last several decades. There are currently over 30 deposits in production in that region, which have collectively produced millions of ounces of gold in this now famous gold district. In contrast, alluvial miners have discovered most of the existing deposits in the paleo-Proterozoic rocks of the Guiana Shield, which stretches from Brazil & French Guiana northwest over Suriname and into Guyana and Venezuela, with very little systematic exploration conducted over this vast region. To date, the Guiana Shield has produced only a few multimillion-ounce deposits, suggesting there are numerous possibilities to discover more world-class gold deposits in the Shields mineral districts.
Many gold deposits have been discovered in the lower Proterozoic volcano-sedimentary sequences in the West African Craton over the last several decades and a number of these are in production. In particular, these mines These include Obuassi, Ayanfuri, Ahafo, Tarkwa, Chirano and Boguso Au deposits in Ghana; the Sadiola, Yatela, Tabakoto, Morila and Syama deposits in Mali; the Sabodala deposit in Senegal; the Essakane, Taparko, Mana and Youga deposits in Burkina Faso and the Tongon, Ity and Bonikro Au deposits in Côte d'Ivoire.
A large part of the Guiana Shield is geologically underexplored because of dense tropical forests and thick lateritic/saprolitic weathered overburden complicating exploration efforts. Increasing alluvial mining and exploration activities since the 1990'shave demonstrated the excellent gold mineralization potential of the area. Significant gold discoveries have been made at Las Christinas, Las Brisas, and El Callao in the Kilometre 88 district of Venezuela, Omai and Aurora in Guyana, Gros Rosebel and Miriam in Suriname, and Montagne d'Or in French Guiana.
The Otomung Concession, 20 km north-northwest of Toroparu, lies in an area that may have similar depositional conditions as Toroparu as suggested by Sandspring's geologic model. The Company has conducted three systematic saprolite-geochemical surveys of the Otomung concession focused on an elongated intrusive structure defined by multi-element saprolite geochemistry interpretation and airborne geophysics.
The results of the geochemical and geophysical programs identify an elongated intrusive in the center of the Otomung concession, and the possible existence of a similar plutonic structure further to the northwest.
The geochemistry surveys along the northeastern contact of the intrusive revealed an 8 km long NW-SE trend. The trend coincides with a magnetic low lineament of the same orientation on the airborne maps.
Mineralized potential within the Otomung Concession has been interpreted to lie within late Paleo-Proterozoic intrusives which indicate a significant regional structure related to Puruni shear corridor may exist which requires additional exploration.