Importance of the study on recharge for the evaluation of potential impact of uranium mining on fractured aquifers. Case study: URA/INB (Caetite, Bahia, Brazil)

The domain of the crystalline rocks, that predominant at the brazilian semiarid, presents fractured type aquifers systems, and their spatial distribution is done in very heterogeneous way, since the underground water depends upon the underground geological characteristics and the climate conditions. So, it is very important to study the geologic structure of the area, observing the depth and distribution of the fractures and failure, their relationship with the topography and with water wells productivity, and it is possible to obtain information explaining the fact that frequently producer and dry wells are placed near to each other, and where are positioned the fractures in the space and how they are connected to each other. Those data will be used in the near future to predict also the fluid mobility, through the use of transport numerical models. In the present study case, the fractured aquifer represents the main water source for the mine industrial complex and for the rural community near the enterprise as well. In this case, the study presents the description of the fractures obtained on tubular wells, relating with topography and physic-chemical parameters of the water. (author)