PhD opportunities

Multi-criteria optimization of uranium exploitation by In Situ Recovery

Thesis proposal

Area of expertiseGeoscience and Geoengineering
Doctoral SchoolGRNE - Gťosciences, Ressources Naturelles et Environnement
SupervisorM. Vincent LAGNEAU
Research unitGeosciences
ContactSEIGNEUR Nicolas
Starting dateOctober 1st 2021
KeywordsReactive transport, In Situ Recovery, Uranium , Environmental impact, Sustainable mining
AbstractWorldwide, uranium production is mostly based on In Situ Recover (ISR) techniques. Today, ORANO Mining is operating one of the largest ISR mine in Kazakhstan and studies several other projects around the world. ORANO Mining partly relies on HYTEC, a reactive transport code developed by MINES ParisTech to plan and optimize their exploitation strategy (Lagneau et al. 2019). The recent work of Antoine Collet, who started a PhD in the Hytec team in early 2021, has further demonstrated the predictive capacities of HYTEC for these techniques. Also, the PhD thesis of Jean Langanay paved the way to optimize production strategies based on a geostatistical analysis of the geological uncertainty. The economic advantages of using a predictive tool for mining operations are obvious.
In parallel, monitoring of the water quality and reactive transport studies are being performed to study the environmental impact of this exploitation (Lagneau et al. 2019; de Boissezon et al. 2020). Several spatial and temporal scales are being investigated, to understand and mitigate the long-term impacts. To achieve this, a more detailed description of the physicochemical processes is required to predict the water quality (Angileri et al., 2020 ; Robin et al., 2020), incorporating secondary mineral precipitation and sorption processes. A coupled model (production + environmental impact) would allow to better comprehend the costs associated to the aquifer remediation. 3D models of the environmental impact of a production block are being performed using Hytec, in the context of the postdoctoral work of Sofia Escario Perez, under the supervision of Nicolas Seigneur and Michael Descostes (ORANO Mining). Based on her work, it is then possible to study several exploitation strategies to find an optimum between uranium production and environmental impact. Also, several aquifer remediation strategies will be studied (natural attenuation or bioremediation ; Descostes et al. 2014).
This PhD proposal will consist of three main steps:
1. Calibration of the hydrogeochemical model based on long-term water quality monitoring data
2. Sensitivity analysis based on the production strategy (injection and pumping rates, solution composition)
3. Definition of economic (U production and remediation costs) and scientific criteria to quantify the environmental impact and provide guidelines to mine operators.
ProfileThe PhD applicant needs to have an interest and a basic knowledge in numerical simulations and programming. Interest and strong knowledge in hydrogeochemistry.
FundingConcours pour un contrat doctoral