
The Cuance and Los Hojanchos Concessions properties lie at the western margin of the Los Ranchos Formation, part of the Early Cretaceous Caribbean volcanic island arc sequence which has been overthrust by volcanic units of the Maimón Formation. The main rock unit of the Los ranchos Formation in the area consists of amygdaloidal basalt with local pillow features. The Maimón Formation in the area is composed of bimodal volcanic rocks. Several small dioritic plugs intrude the basalt along the southern edge of the concessions. Low-grade metamorphism attributed to seawater hydrothermal systems is overprinted by extensive zones of argillic alteration and silicification. Extensive zones of argillic alteration and silicification affect the central part of both concessions (see geological map). Pueblo Viejo is located 7 kilometers to the north of the Cuance Concession.
The primary exploration targets are massive sulphide and epithermal deposits within the Los Ranchos and Maimón Formations on the Cuance Concession. Detailed mapping and sampling on the Cuance-Los Hojanchos Joint Venture Concessions has identified a series of "kill zones" where the lack of vegetation results from high sulfide levels in the soils and indicates the presence of sulfide minerals in the underlying rock units. These zones are coincident with propyllitic and argillic alteration, and massive to semi-massive bands of sulfide mineralisation seen in road cuts and stream profiles.
A number of ground geophysical surveys have been carried out across these anomalous zones in order to prioritize drill targets. Most of the area of the concessions has been covered by regular soil geochemistry grids.
Two areas have been drilled on the Cuance Concession:
A detailed petrography study completed on samples from Loma Lambedera indicates that mineralisation represents volcanic massive sulphide stringer phases, leaving an open target for massive mineralisation in the vicinity of the drilled area.
Two previous drilling programs in 1999 and 2004 targeted geophysical anomalies identified from ground induced polarisation and resistivity surveys across the northern part of the Los Hojanchos Concession. Short intervals of copper mineralisation were intercepted (up to 1.5 meters grading 1.58% copper) and minor gold mineralisation. In light of the favourable exploration results on the Cuance Concession, activity is limited on the Los Hojanchos Concession.