The geological setting for the Tilemsi concession consists of a bed of phosphate rock within an Eocene sequence of sedimentary beds dipping gently to the west. The bed of phosphate rock occurs on hills in the region but has been eroded away where valleys occur. Phosphate is found within the mineral apatite.
A preliminary program of sampling and mapping within the Tilemsi concession was completed in the summer of 2009. During the program, 26 grab samples were taken from exposures of rock over a distance of 6,870 metres along the southeast and south side of the Alfatchafa hill where a layer of phosphate rock occurs within a Middle Eocene sedimentary sequence (Geological Map of Alfatchafa Area
). Results of the analyses of these samples ranged from 5.11 to 33.05% P2
and averaged 24.50% P2
. The thickness of the zone of phosphate rock, where observed, ranges from 0.40 to 1.7 metres.
The depth of the phosphate rock on the southeast side of the hill is approximately 8 metres. It is overlain from top to bottom by phosphate rock with laterite, phosphate with gravel, phosphate with laterite, phosphate with clay and finally pink clay and yellow sandstone.
Limited mapping and sampling was completed over the Tin Hina phosphate occurrence. This includes the Tin Behouki hill. The Tin Hina concession will be the focus of additional mapping and sampling during the next program. In addition, the other hills within the concession where the phosphate layer is likely to occur include the In Tassen, In Arfan and Tin Tanerouet.