The Achmmach tin deposit is hosted within the turbiditic sediments of the Namurian aged Fourhal Formation. The Fourhal Formation consists of deformed, interbedded pelites and psammites of lower carboniferous age. These meta sandstones and shales comprise a tightly-folded sequence of turbidite beds, overprinted by tourmaline alteration within sheared regions and intruded by magmatic sills.

Mineralisation is localised in two subparallel ENE striking lodes named the Meknès and Sidi Addi Trends, separated by a distance of approximately 500 m. The largest part of the resource comprises the Meknès Trend. The mineralisation to be mined within the Sidi Addi Trend is referred to as the Western Zone. It is developed within the tourmaline-silica altered metasediments. Tin mineralisation occurs primarily as cassiterite with minor stannite.

The Achmmach tin deposit is hosted within a sedimentary sequence of turbidite beds that vary from thin-bedded to graded-bedded cyclic. Tourmaline-silica breccias were formed during subsequent deformation, and following this a number of pulses of mineralisation occurred, with the tin mineralisation preferentially (but not always) precipitating in the pre-existing tourmaline silica breccias. The tin occurs as disseminated cassiterite (SnO2) associated with sulphide and/or quartz veins.

Overall tin mineralisation at Achmmach extends 1.6km in strike length, is 300m wide and extends from the surface to 600m below the surfac ........

The primary mining method to be used for the Achmmach deposit is conventional mechanized longhole stoping. As the geometry and thickness of the mining shapes vary throughout the different lodes, a combination of bottom-up cemented rock fill (CRF) and top-down open stoping methods is planned.

CRF is a simple method of backfilling which involves placement of waste rock mixed with cement slurry into the stope void by a loader from a drive at the top of the stope. Stoping will be carried out by retreating from the extremities to a central access.

There are three zones defined by deposit geometry and proposed mining method: the Central Zone, Eastern Zone and Western Zone. For scheduling purposes, the Western Zone has both mining methods applied, with bottom-up CRF above 1015 mRL and top-down open stoping below this point.

Central Zone Mining Method
For the generally thick Central Zone (in places up to 20 m in width), a bottom-up mining sequence utilizing CRF will be implemented. A top-down method with no fill, leaving pillars behind for stability was also analysed but this significantly reduced the recovered tonnes due to the required widths of the pillars.

Eastern Zone Mining Method
The Eastern Zone area will be mined using a top-down no-fill method, leaving behind in-situ pillars for stability. The pillar size factors have been extrapolated across the entire Eastern Zone area based on detailed geotechnical design for the Ea ........

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