Université Abdou Moumouni, Faculté des sciences et techniques, Département de Géologie, Laboratoire Eaux Souterraines et Géoressources, BP: 10662 Niamey, Niger
This study is concerned with the 2D modelling of the mineralised units of the uranium deposit at the Nord-Taza Satellite prospect (Arlit, Northern Niger). The Nord-Taza Satellite prospect, operated by Aïr Mines Company (SOMAÏR), is an integral part of the uranium deposits in the Arlit sector, which are hosted by sandstones of Carboniferous age and deposited in a fluvio-deltaic environment. The methodological approach adopted consists of correlating the data obtained from development drilling and facing surveys using modelling software such as Surpac and Sermine. The minerals present include orthoclase, quartz, biotite, zircon, monazite and apatite. The lithological analysis showed that the study area is characterised by coarse sandstones with microconglomeratic tendencies, argillites and finely consolidated sandstones. These facies, referred to respectively as Unit 1 (U1), Unit 2 (U2) and Unit 3 (U3) of the Tarât, are the host formations for the uranium mineralisation in the study area. Correlation of data from boreholes and face surveys has shown that high uranium grades are found in the reduced sandstones of units U1 and U3, while low grades are found in the mudstones of unit U2. Information obtained from the Surpac software showed that uranium mineralisation is oriented in a north-south direction and is more concentrated on the western flank of the study area near the Arlit normal fault-flexure. The 2D model produced using the Sermine software showed that U1 has stratiform mineralisation, U2 has discontinuous or isolated lens mineralisation and U3 has chenalising lens mineralisation. The U4 or Madaouéla unit is not mineralised in the Nord-Taza Satellite prospect.