The Boumadine deposit is described as shallow mineralizing system similar to volcanic-hosted epithermal veins developed in subaerial resurgent caldera environments (Bouabdellah and Levresse, 2016; Abia et al., 2003).

Mineralization is structurally controlled, consisting of zones of vuggy quartz and veins, veinlets, and tectonic-hydrothermal breccias.

Three successive and overlapping stages of mineralization are distinguished (Ait Saadi, 1992; Abia et al., 2003; Bouabdellah and levresse, 2016). The origin of the mineralization is probably the mixing between ascending deep seated fluid and meteoric waters that have generated precipitation of precious- and associated base- metal mineralization.

The Boumadine mineralization is structurally controlled and comprises a system of subvertical veins, veinlets, cemented breccias within veins and filling of tension gashes veins. Mineralized structures occur exclusively within the rhyolitic sequence of the Tamerzaga Formation.

The orientation of the mineralized structures is related to Ediacaran transcurrent tectonics represented by N30 to N-S strike-slip fault zones (Freton, 1988; Ait Saadi, 1992; Abia et al., 1999, 2003). The mineralization and associated alterations are developped at the proximity of magmatic vents. Alteration, which appears around the mineralization, develops an assemblage of major quartz and white micas with minor quantities of chlorite and calcite (Ait Saadi, 1992).

At least five mineralized vein systems are documented at Boumadine deposit. IMARIREN zone, Tizi, NORD zone, CENTRE zone and SUD zone. The rich mineralization tends to occur where NNE, NNW and the textural features indicate that mineralization took place in open space with a relatively shallow mineralizing system (Abia et al., 1999).

All of the mineralized veins display more or less similar mineral assemblages. The mineral sequence established on the crosscutting relationships show three stages of mineralization (Abia et al., 2003; Bouabdellah and Levresse, 2016).

Stage I is characterized by the mineral assemblage dominated by massive pyrite with banded appearance, pyrrhotite, cassiterite and arsenopyrite emplaced under N160 E shortening.

The stage II is characterized by the precipitation of sphalerite, chalcopyrite, calcite, quartz, tetrahedrite-tennantite, silver, gold and Bismuth hosted in massive quartz veins, stock work veins and hydrothermal breccias. Gold is mostly distributed in pyrite and arsenopyrite crystals, and less frequently in galena and sphalerite. Galena is mainly present as a cement of the earlier brecciated sulfides and partially dissolving the arsenopyrite, pyrite and sphalerite. Quartz crystals are filling cavities within all pre-existing sulfides and mainly associated with small euhedral arsenopyrite crystals. Structural and textural data indicate that mineralization took place during the late Neoproterozoic as a result of open-space filling.

The stage III is resulting from the oxidation of primary sulphides and consists of minor amounts of goethite, and jarosite with traces of hematite.

These data further suggest that the Boumadine deposit represents a relatively shallow mineralizing system that was open to the surface, and is similar to volcanic-hosted epithermal veins developed in subaerial resurgent caldera environments (Abia et al., 2003).

In Boumadine, there are five (5) mining zones called: CENTRE, SUD, NORD, TIZI and IMARIREN.

The mining should start with a small open pit at IMARIREN that will produce 100,000 m.t. per year for two years. During the same period, a ramp from surface will be started for the zones CENTRE and NORD to be ready to produce 1500 m.t. per day. That to include the IMARIREN open pit’s production for two years starting on year 2021. For the economic analysis in cash flow, it is assumed that all resources are mined by underground method.

All infrastructures, such as plant, offices, garage, warehouse etc., will be located at the CENTRE zone due to the fact that it is the biggest zone in tonnage of the five (5) zones forming the deposit.

Starting year 2023, the production will increase to 2000 m.t. per day up to the end of the mine life, which is scheduled for 2033 if there is no other addition to the actual total tonnage. We are assuming 330 days of mining production per year.

During the year 2026, a ramp will start for zone SUD. The same is planned for zones TIZI and IMARIREN during the year 2028.

The various zones of the deposit are located in competent rock and have steep overall dip, making it easily mined using free falling method as well as cut and fill method (same method than Zgounder). It is recommended to use the open long hole mining method as much as possible, with sub- levels for the proposed new mining sites.

The Nord zone is wide and will be in the longhole stoping category.

The five (5) zones will have a main ramp from the surface and will have a second exit for ventilation and the escape way from the actual shafts from CENTRE, SUD and TIZI and from a new raise development for IMARIREN and NORD from bottom to surface. Raise extensions will have to be completed to connect the actual shaft and the bottom of the zones SUD, CENTRE and TIZI. Raising will be done by Alimak method.

The various main ramp will have a dimension of 4.5 m by 3.5 m.

Each zone will have its own compressed air system, electricity, explosive magazines and a backup generator in case of power loss to keep the underground ventilation working.

For mining equipment, one (1) boom jumbos, a scooptrams (3t.) and a five (5) cubic meters dumpers will be the main equipment used.

During the life of the mine, the mining equipment will go from one zone to develop another zone thus saving capex on equipment due to the fact that each zone will be mined more or less the same way and not at the same time.

Since, there is no production shaft but only a main ramp for each zone, all mineralized material will be hauled via trucks up to the surface and transferred into bigger trucks to be hauled at the plant near CENTRE zone. Production shaft is not viable for now due to the shallowness of each zone.

Crushing
Mining material grading approximately 1.03% Pb, 3.00% Zn, 1.67 g/t Au, 101.76 g/t Ag and Ge from 7.2 to 25.92 g/t will be hauled from the open pit and/or the underground openings by off the road trucks and whenever possible is dumped directly on a static grizzly. However, because the mining and crushing operations will not always be on the same time schedule, it is assumed that 25% of the time the haul trucks will proceed to a RoM stock pile and the rest of the time will dump directly onto the grizzly above the crusher feed hopper. The RoM stockpile area is sized to hold approximately 5,000 tonnes of ore. Secondary handling of the ore will be by a front-end loader that will, among other things, be used to feed the crusher hopper with stockpiled RoM ore as necessary.

Because of the underground mining method (long hole) and open pitting, some part of the incoming feed will be coarser than the grizzly apertures. The oversize will be broken in place with a stationary hydraulic rock breaker. From the grizzly the ore falls into an out of mine ore hopper. The hopper feeds via a vibrating feeder a jaw crusher. From the jaw crusher, the material falls on a first conveyor belt feeding a coarse ore bin. From the coarse ore bin, the ore is conveyed to a double deck screen in close circuit with a Symons short head cone crusher. Screen undersize (10 mm) is conveyed to two fine ore bins in parallel. Each fine ore bin has a dedicated feeder at the bottom. Before entering the mill, the ore is weighed with a weight-meter installed on the conveyors feeding the rod mill.

All in all, crushing capacity is approximately 100 tonnes per hour.

Grinding
From the fine ore bins, the material is conveyed to a rod mill. Rod mill discharge is pumped to a set of cyclones. Cyclones underflow flows by gravity to a ball mill. Ball mill discharges into the same pump box as the rod mill and is pumped to same set of cyclones. Circulating load will be in the 300% range.

Cyclones underflow will flow by gravity back to the ball mill while cyclones overflow at a fineness of approximately D80 = 105 µm will flow by gravity to a reagents conditioner before flowing also by gravity to the first cell of the lead flotation rougher.

The process plant will be designed to recover the lead, the zinc, the gold, the silver and the germanium from the fresh ore and the old tailings by a combination of flotation, pressure oxidation and cyanidation. For the fresh mine material the mill will incorporate the following sections : run-of-mine ore storage, a two-stage crushing plant, crushed ore storage, a double stages grinding bay with cyclone classification, lead, zinc and sulfides flotation, pressure oxidation of the sulfides concentrate, leaching (cyanidation) of the gold and the silver, refining and finally a water and reagents distribution system. For the old tailings, the process will be the same except that since the lead and the zinc were already floated and recovered during the 1989-1992 mining- milling operations, there will be no crushing, grinding or flotation. Process of old tailings will be done whenever there will be shortage of fresh ore from the mining operations. Even if for the first two years of operation ........