## 4 Conclusions  
This paper represents the first mineralurgical and environmental characterization of the iron oxide-copper-gold (IOCG) ore of Guelb Moghrein, Akjoujt Mauritania. Our key findings indicate that the physical properties of the TSF tailings exhibit very low plasticity for (TSF1) and low plasticity for TSF2 and TSF3, revealing silt-sized material characteristics. Our study shows that the chemical compositions of the TSF tailings and salt precipitates contain high Fe\({}_{2}\)O\({}_{3}\) contents. TSF1 and TSF2 tailings are characterized by high magnetite contents, which are recovered in the magnetite processing plant using wet low-intensity magnetic separators (WLIMSs). TSF3, which is obtained after magnetic separation, contains the lowest levels of Fe\({}_{3}\)O\({}_{4}\). We also find that SiO\({}_{2}\) and MgO are present with lower contents in the TSF tailings and salt precipitates with respect to Fe\({}_{2}\)O\({}_{3}\). Compared to the UCC, these samples are enriched in Cu, As, Th, V, Ni, Co, Se, Sb and Cd with lesser amounts in Zn and Pb, but they are significantly depleted in Zr, Sr and Ba. After flotation processing, TSF1 shows relatively high levels of Cu (0.26%) and Au (1.02 g/t) that are recovered from a primary ore grading 1.88% for Cu and 1.41 g/t for Au. The geochemical process related to the oxidation of iron sulfides and the dissolution of neutralizing minerals (carbonates and silicates) involves the formation of numerous secondary minerals such as oxyhydroxides, arsenates, sulfates, oxyhalides and halides. Our results also show that the secondary minerals precipitation stems from the formation of highly indurated crusts on the surface of the TSF tailings. At the surface of the tailings, water evaporation results in salt precipitation (hexahdrite, paratacamite, kieserite, cobaltkieserite, aplowite, starkeyeite, gypsum, halite). The static mine drainage prediction tests, related to environmental conditions, showed that the bases generated mainly by the dissolution of carbonates and silicates take over the acids which come mainly from the oxidation of sulfides. These tests indicated that for the TSF1 and TSF2 tailings, the AMD is uncertain, while the TSF3 mine tailings is classified as non-acid generating. Thus, and based on the neutral pH paste imposed by a silico-carbonate matrix with a high neutralizing potential, the leaching of the TSF tailings results in contaminated neutral drainage (CND). To further improve and extend our study in order to avoid harmful geo-environmental impacts, we envision developing an approach that optimizes the management of the TSF during mine operation with the objective of facilitating the rehabilitation phase after site closure. Conceptualization, N.B.B., F.S. and I.K.T. ; Methodology, R.S, F.S. and N.B.B. ; Formal analysis, N.B.B., F.S., B.B. and F.M. ; Writing--original draft, N.B.B. and F.S. ; review & editing F.S., R.S., N.B.B. and M.A.B. All authors have read and agreed to the published version of the manuscript. This research has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement n\({}^{\text{o}}\) 952306. The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy. The authors would like to thank [PERSON], who was, at the time of this work, working in the Ministry of Petroleum, Energy and Mines, for his administrative support. Our gratitude is also extended to the Society of Mauritanian Copper Mines (MCM) for the authorization access we were granted to the Guelb Moghrein mining site as well as the logistical and scientific support. Our thanks also go to the laboratory of analytical chemistry of the Office National des Mines (ONM) in Tunisia. The authors are grateful to [PERSON] from the English Department of the College of Humanities, University of Tunis, for his kind and thorough reviews in this manuscript. The authors declare no conflict of interest. * [PERSON] et al.