Evaluation of the Behavior of the Sealing Grout of the Mining Holes and Verification of the Conformity of Mixing Water and Izegouandane and Tarat Aquifers: Case of Mining Company of AKOUTA (COMINAK)

Abstract

The aims of this study is to identify the behavior of the sealing grout in the Izegouandane and Tarât aquifers, which are the main water supply sources in the northern region of Niger, in order to prevent contamination and reduce the impact of uranium mining activities on the groundwater. This study also made it possible to evaluate the conformity of the mixing water as well as the bearing capacity of the grout in the aquifers crossed in order to verify its conformity. The study area is located in a desert zone in the northern band of Niger, in Arlit city. The measured compressive strengths are 60 bars for cylinder A, 52.5 for cylinder B and 62.5 for cylinder C with an average value of 58.33 bars. The deduced base stress value is 2.24 MPa. The sampled mixing water has a pH of 8.7 with a suspended solids content of 0.02g/l, a Cl- concentration of 93 mg/l and nitrate and nitrite concentration values that are 5 mg/l and 12 mg/l respectively. These waters comply with the general specifications of the standards relating to the quality of mixing water and can therefore be used to fill in boreholes. The analysis of groundwater shows that for Izegouandane and Tarat aquifers the values of concentration of suspended solids are respectively 0.04 g / L to 0.001 g / L. The values of Ph of these waters are 8.7 and 8.1 respectively for the water table of Izegouandane and Tarat. The analysis of Izegouandane aquifer showed that the concentrations of chloride, nitrates and sulfates are respectively 32 mg/L, 9 mg/L and 36 mg/L. Those of magnesium, ammonium and carbon dioxide, they are respectively 1.5 mg/L, 0.8 mg/L and 0.5 mg/L. For the Tarat aquifer, the concentrations of chloride, nitrates and sulphates are respectively 47 mg/L, 29.5 mg/L and 47 mg/L. As for magnesium, ammonium and carbon dioxide, they are respectively 10.02 mg/L, 1.6 mg/L and 1.6 mg/L.