The Dasa Project is located in north-eastern Niger inside the Tim Mersoï sedimentary basin. The basin covers an area of some 114,000 km2 and is part of the much larger Iullemeden Basin (Palaeozoic-Tertiary) that stretches into Mali, Algeria, Benin and Nigeria.
All known uranium occurrences and deposits in Niger are all classified to belong to the sedimentary tabular, paleo channel and roll-front or sandstone types.
In the Dasa deposit, characteristics more consistent with the paleo channel tabular type seem to prevail.
The uranium in many of the deposits of the Tim Mersoï Basin is oxidized. Among the primary tetravalent minerals, coffinite is dominant and accompanied by pitchblende and silico titanates of uranium. Uranium hexavalent minerals such as uranophane and meta-tyuyamunite are present in the Imouraren and TGT-Geleli deposits.
The gangue is composed of quartz, feldspar, analcime and often illite, kaolinite and chlorite; with accessories such as some zircon, ilmenite, magnetite, tourmaline, garnet, anatase and leucoxene.
The uranium minerals are frequently associated with copper minerals (native copper, chalcocite, chalcopyrite, malachite, chrysocolla) and also with iron minerals such as pyrite, hematite and goethite. Organic plant materials are generally plentiful in un-oxidized facies of greyish-greenish colour.
The Dasa deposit site corresponds to a major structural intersection of the Adrar-Emoles fl ........
