During the reconnaissance mapping of the northern and central part of the permit, the underground workings which form part of the Pesqueiras mine were studied and sampled. Figure 1 is a sketch map of the distribution of the galleries.

These underground workings are situated between two open cast pits and cover an area of about 100m x100m. Mine workings are more irregular in the eastern zone of the permit, becoming more ordered towards the west.

Four different gallery levels were defined following the dipping of the main pegmatite structure. The mostly well-kaolinized albite pegmatite reaches thickness of 8m.