OICC Press Iranian Journal of Earth Sciences 2228-785X 17 1 2025 01 10 Geochemical analysis of the Maastrichtian phosphate stratum “Couche 3” and its exploitability in the Sidi Daoui mine (Ouled Abdoun, Morocco) 1 7 10.57647/j.ijes.2025.1701.01 EN Abderrahim Ayad Earth Sciences Department, Abdelmalek Essaˆadi University, Morocco https://orcid.org/0000-0001-6999-6086 Journal Article 2025 01 10 The Couche 3 (C3) of Sidi Daoui has long been considered an unexploitable low-grade phosphate stratum and was left behind. Nowadays, with the exhaustion of high-grade phosphate resources, the l’Office Chérifien des Phosphates (OCP) Group plans to launch the exploitation of C3 by private mining companies. This study was undertaken under the authority of Sidi Daoui's exploitation service, IDK/CP-467 to investigate the feasibility of launching the exploitation of C3 in Sidi Daoui. Phosphate samples were taken from the stockpiles and analyzed for BPL (Bone Phosphate of Lime) and impurities. The analysis shows that the C3 of Sidi Daoui belongs to the category of low-grade phosphates, with a vertical gradient decreasing from the top (upper C3) with 61.42% BPL to the bottom (lower C3) with 58.59% BPL. Through these results, it is concluded that the upper C3 can achieve a relatively medium grade product, by using a selective exploitation method accompanied by a relevant and suitable mining processing approach, or by mixing its phosphate with that of high-grade strata coming from other mines such as Sidi Chennane, MEA Lahrech, or El Hlassa.