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Orinoco Gold Limited (ASX: OGX) (Orinoco or the Company) is pleased to announce the conclusion of the extensive panel sampling programme along the Cuca vein accessed via the historic Cuca development. Cuca mineralized veins are part of the same mineralized system that contains Cascavel and Mestre mineralized veins.

Geologically, the Cuca Mineralized Level is located below the Mestre Level, separated by the Cascavel Dolomite layer that hosts a carbonate replacement silver-tungsten-copper mineralization. The orientation of the veins is slightly different and is controlled by the main regional fabrics, dipping to the South West. However, stretching lineation which is interpreted to control the high-grade shoots is the same as in the Mestre level, plunging gently to the West. Detailed geological mapping was also carried out in parallel with the sampling.

The gold occurrence in Cuca is similar to Cascavel and Mestre, being mostly free and coarse gold. The distribution of gold in the Cuca vein appears to be more consistent than the Cascavel zone which will potentially support more consistent grade recovery during mining. Visible gold was observed frequently in the veins exposed and sampled. The vein shows thicknesses of up to 50 cm (varying from 10cm to 50cm) and is continuous along areas mapped in the historic workings. The veins show the same strong sericite alteration halo as the Cascavel and Mestre veins.

A distinctive feature of the Cuca mineralized veins is the presence of sulphides (which are mostly oxidized) compared to the Mestre level ore zone. Where the sulphides (mainly pyrite) are oxidized, the vein has a reddish colour, when the sulphides are unaltered the vein has a dark grey colour.


Underground samples were collected either as panel samples. Panel samples were 2 metres long (to ensure representability in a coarse-grained gold environment), taken continuously along the vein throughout the old workings, weighing approximately 20 kg. The panel vertices were surveyed by a qualified surveyor using an electronic Leica total station to guarantee precision in the sample location.

The maps (see attached release) show the surveyed location of the samples along the winzes and the distribution of the results.

A targeted drilling program (from both underground and surface) is currently being prepared with the aim to confirm the continuation of the Cuca zone along its strike (to the South and North) and down plunge. Bulk sampling of the vein is planned once ground conditions are improved in the historic development.