The Essaouira Basin (Morocco) contains a multi-layered aquifer situated in fractured and karstic materials from the Middle and Upper Cretaceous (the Cenomanian, Turonian and Senonian). Water percolates through the limestone and dolomite formations of the Turonian stage either through the marls and calcareous marls of the Cenomanian or through the calcareous marly materials of the Senonian. The aquifer system may be interconnected since the marl layer separating the Turonian, Cenomanian and Senonian aquifers is thin or intensively fractured. In that case, the water is transported through a network of fractures and stratification joints. This paper describes the extent of the nitrate pollution in the area and its origin. Most of the wells and drillholes located in the Kourimat perimeter are contaminated by nitrates with some concentrations over 400 mg l −1 . Nitrate contamination is also observed in the surface water of the Qsob River, which constitutes the natural outlet of the multi-layered complex aquifer system. In this area, agriculture is more developed than in the rest of the Essaouira Basin. Diffuse pollution of the karstic groundwater body by agricultural fertiliser residues may therefore partially explain the observed nitrate pollution. However, point pollution around the wells, springs and drillholes from human wastewater, livestock faeces and the mineralisation of organic debris close to the Muslim cemeteries cannot be excluded.  2003 Académie des sciences. Published by Éditions scientifiques et médicales Elsevier SAS. All rights reserved. Résumé Le bassin d'Essaouira (Maroc) renferme un système aquifère multicouche contenu dans le Crétacé moyen et supérieur (Cénomanien, Turonien et Sénonien). Les circulations d'eau entre étages adjacents sont possibles à travers des niveaux marneux peu épais et intensément fracturés. La présence des nitrates dans des proportions extrêmes reste problématique (400 mg l −1

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The Upper Jurassic Evaporite Formation accumulated up to 200 m of interbedded gypsum-carbonates layers across the coastal cliffed region of Safi (Morocco) have been affected by karstification process, resulting in karst collapse and subsidence structures associated with faulting, fracturing and different types of instabilities, which are among the main causes of natural hazard risk, impacting the socio-economic and environmental issues. Surface investigation (physiognomic approach) allowed the characterization and identification of deep-seated and subjacent gypsum interstratal stages and showed that the karstic features are controlled by orientations of faults and fractures. To highlight the relationship between tectonics and karstification, in this area, fracture orientations were studied, and the result of analysis of diagrams showed that, in most cases, orientations of karst landforms are controlled by regional tectonic features.

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<p>In Morocco, no measures have been taken to manage residual waste from operational or abandoned mining and quarries sites.</p><p>Indeed, significant quantities of mine waste, composed of concentrator residues and sterile waste, have been abandoned after the closure of operations without any effective management or rehabilitation planning.</p><p>These residues could have harmful impacts on the environment: soil and water pollution, destruction or disturbance of natural habitats, visual impact on the countryside...</p><p>The valorization and sustainable management of mining waste appear to be adequate solutions to major environmental problems. The construction sector can be a profitable sector to absorb chemically stable mining waste.</p><p>The objective of this research work is to study the feasibility of recycling waste from the abandoned Kettara mine (Morocco) and gypsum waste rock in Sidi Tijji (Morocco) as raw materials in construction materials.</p><p>The study consists first of a geological characterization and then a characterization of the physical, chemical and mineralogical properties of the residues, followed by an evaluation of the mechanical properties of the composite mixtures based on the chemically stable residues.</p><p>The Kettara mine is located in the Jbilet Central Mountains, 30 km northwest of Marrakech. Geologically, the pyrrhotite district of Kettara corresponds to the outcrop area of the volcano-sedimentary series of Saghlef shales. For the gypsum quarry at Sidi Tijji, which is part of the Safi basin, characterized by Jurassic outcrops essentially formed by gypsum and carbonate formations.</p><p>Mineralogical and chemical analysis have shown that these waste products are still rich in minerals such as the waste from the Kettara mine; the FeO3 concentrated amounts to 55.6%. In addition, gypsum waste rock represents a concentration of 28.9% CaO. Therefore, a low water content for the majority of samples.</p><p>Adapting to the principles of integrated recovery and management of mining and quarry waste requires a cultural change within the industry, but also in the ministries concerned.</p><p><strong>Keywords</strong>: Valorization, mine waste, mines and quarries, construction materials.</p>