The Khemisset Basin is a sedimentary basin of Triassic age, initiated by the opening of the mid-Atlantic ridge. The sedimentary sequence of the basin is characterised by early continental red bed deposits including iron-rich sandstones. Continued subsidence and extensional faulting in the late Triassic and early Jurassic resulted in the deposition of clay and extensive evaporite sequences, characteristic of a closed marine basin and thought to exceed 1,000m in thickness in some areas. The evaporitic sequence is primarily comprised of halite, gypsum and locally, sylvite and carnallite.

The Khemisset basin was characterised by a continental slope leading into a shallow marine environment with the deposition of carbonate banks and the formation of a carbonate platform with associated dolostone and dolomitic limestone deposits. Around this time Western Morocco also experienced the deposition of extrusive basalts. Subsidence in the Moroccan continental margin continued into the Middle Cretaceous, until a period of uplift in the Late Cretaceous leading to salt diapirism; the intrusion of salt into surrounding host rock to form domes. As the rate of subsidence slowed, the basin became erosive leading to the deposition of a thick Tertiary sedimentary sequence of marls and conglomerates.

The evaporite sequence is equivalent to the Lower Salt Formation observed within the Khemisset basin and represents a regional target for potash exploration.

The following basic design assumptions have been made:
• There is no overlying aquifer and no water occurs in the potash seam;
• No flammable gas occurs in the potash seam;
• Geotechnical design can be based upon general geotechnical parameters derived from existing potash operations;
• The salt beam (Lower Salt Formation) between the potash horizon and overlying Basalt Unit is contiguous with the basalt and can be supported through appropriate room sizing with systematic roof bolting in main roadway developments only;
• The potash horizon floor elevation is relatively planar and does not compromise the mine design in terms of access and mineral recoveries;
• No major faulting occurs across the deposit area;
• Panel room orientation is not affected by in-situ stress fields;
• Selective mining of sylvite is not proposed;
• Backfill is not proposed nor required in Morocco;
• The production target is approximately 6.0 Mtpa ROM which will allow for a 19-year life of mine.

The Company has elected to use contract mining for both production and development.

The mine is proposed to be accessed via twin declines from the surface which will enable ore to be extracted using a conventional room and pillar mining methodology using continuous miners.

The decline will be driven through three key lithologies: minor clay formation (~10m thick); primary massive salt horizon (~320m thick); and an overlying basalt ........

To account for the mixed ore feed, all mixed ore must be crushed through both stages of crushing to a size of 0.4 mm and all ore must be processed through a mixed ore decomposition. The first stage of crushing is open circuit crushing to bring the ore to 12-15 mm before reporting to a second stage of closed circuit crushing to reach the 0.4 mm size requirement. Testing determined the 0.4 mm size requirement for efficient rinneite decomposition. When no Rinneite is present, only the first stage crush is required.

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