In situ recovery is today the first mining extraction technique worldwide for uranium production. The technique has numerous advantages, including low production costs and a limited footprint on the surface. However, the exploitation is complicated by the large spatial variability of the concerned ore bodies and no direct visibility of the ore body. Decision-making is based on a combination of site characterization (geological model, geostatistical model of grade distribution) and empirical or analogical estimations of behavior of the field.
The work proposed in this project aims at giving strong phenomenological grounds to the description of the system. A better understanding of the phenomenon at stake (fluid flow between the wells, geochemical reactions) and a correct parameterization from observations (field data, thermodynamic data and experiment results) allow for reactive transport simulations with predictive capability for the production blocks, even before their production starts. Preliminary results showed the potential of this approach. Also, they highlighted scientific and technical challenges, among which the necessity to improve the description of the chemistry of the system and to master the impact of spatial uncertainty.
The improvement of the predictive capability of the model has direct implications on production optimization. The use of models to test alternative production scenarios leads the way to finding optima following operational criteria (for instance cost or recovery). Optimization at a more global scale can be reached by the integration of such predictions in mining planning: improved management of the concentration fluctuation for each block, allocation over the well field (flow rate, reagents), under the operative constraint of the plant and the global production target of the mine.
Another implication of the project is the improvement of the notion of recoverable reserve. The specificities of the ISR technique modify classical mining notions such as cut-off grade or mineralized envelope. With the integration of information both on the ore geometry and uranium mobilizing processes, the project can improve this notion capital for the ore valorization.
The project is an opportunity for the Geosciences Department to display its methods and expertise, to improve them in a non-conventional mining application central to its research strategy. The project is in line with the mission the Department and more generally ARMINES and MINES ParisTech: economic players oriented research. Finally, the expertise gained within the project will prepare the way to other applications of the ISR technique, towards less soluble metals or less favorable geological media.
AREVA Mines will prepare new tools for the optimization and rationalization of the production at different levels. The integration of the new methods is key, both within an operational tool and more broadly within the decision stream. Other than the production stakes, AREVA Mines’ improved expertise will strengthen its position when applying to future operating licenses.
Monsieur Vincent LAGNEAU (Association pour la Recherche et le Développement des Méthodes et Processus Industriels)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
ARMINES Association pour la Recherche et le Développement des Méthodes et Processus Industriels
Help of the ANR 900,182 euros
Beginning and duration of the scientific project: October 2016 - 48 Months