The Zgounder deposit is described as a Neoproterozoic, epithermal, hypogene system and shares common characteristics (e.g. Age, Ag-Hg mineralization and epithermal-type model) with the giant Imiter deposit (Marcoux and Wadjinny, 2005).

The origin of the Zgounder silver mineralization are thus Na-Ca brines and the main driving mechanisms for silver deposition are associated with the dilution and cooling process (Essaraj et al., 1998).

The silver mineralization occurs at the top of the Brown Formation (sandstones) mainly along the contact and within the dolerite sill. The economic silver concentrations at Zgounder are present mainly as vertical columns, complex clusters, shear zones, veinlets and at the intersection of the E-W and N-S fractures, preferentially at the contact zone between schist and dolerite, (Petruk, 1975; Popov et al., 1989).

Within the bodies, mineralization occurs in millimetric beds, pyritized, as well as veinlets filled by quartz cement and sulphides. Native silver is observed in complex sets of microfractures, mainly at intersections with sulphide veinlets and locally accompanied by a chlorite rich alteration. Small Ag grains (average size of 50 µm) are also found in corrosion zones of early sulphides or disseminated within the schist and dolerite. Tension gashes originally trapped the silver mineralization within a NNE-oriented shear zone affecting the shalesandstone beds (Brown Formation) that contain anomalous Ag values. The silver was then likely remobilized by EW-oriented structures forming isolated Ag-mineralized lenses and fissures. The silver mineralization extends laterally over 1,000 m with a subvertival dip to the south. The vertical extension of the body is offset by sub-horizontal faults with a northward movement of 10 to 30 m, pushing the mineralized zones in steps or blocks (Bounajma, 2002).

Underground mining
At Zgounder the mineralized zones are generally vertical with irregular shapes and scattered mineralization. The cut and fill mining method is now used for exploitation and this method is considered ideal for steeply dipping high grade deposits. This mining method is also highly selective where high grade sections can be mined separately from the low grade rock that will be left in the stopes.

Cut and fill mining excavates the mineralized material in horizontal slices, starting from a bottom undercut advancing upward. The material is drilled, blasted, loaded and removed from the stope which is then backfilled with waste rock. The fill serves both to support stope walls and as a working platform when mining the next slice. Backfill selection is dependent on the quality of the host rock and the size of equipment working on top of the backfill.

Since the mine has previously been in production, few new developments are required above 2000m. The total required additional development required is estimated at 20% of mineralized material tonnage with an estimated average of 3.0 linear meters per working day. Provision in the capex sustaining capital for an average of around 6.0 linear meters per working day, including the ramp (3.4m x 4m section), for a total of 4,691 meters for the major access and a 315m internal shaft for the life of the mining operation (LOM).

The intent of Maya is to stepwise increase the Zgounder mill feed rate from +/- 200 tonnes per day to 2,000 tonnes per day.

First step is to increase the mill feed rate to 500 tpd (2018 -2020).

Second step is to increase the mill feed rate to 2,000 tpd (2020 -2027).

The 500 tpd process plant designed to recover the silver by a gravity-flotation process followed by the cyanide leaching of the gravity and the flotation concentrates will comprise two different entities.vThe upper mill (located at higher elevation), designed by Yantai Xinhai Mining Research & Design Co., Ltd. (Xinhai), which will be located some 1,5 km from the actual mill (actually under construction at the moment of writing this report) will incorporate the following sections : run of mine ore storage, a three stage crushing plant, two 500 tonne fine ore bins, a two stage grinding bay integrating gravity, a flotation section followed by gravity and flotation concentrates thickening and r ........