Element Commodities

The district of Taroudant is located in the headwaters of the plain of Souss, some 70 km east of Taroudant. It is separated from the mine at Imini by the gentle dome of Sirwa, around which are outcropping strips of Cretaceous which in turn encase the manganese mineralization present in the district.

The district consists of two small Cretaceous basins, firstly the basin of Tasdremt to the west which is some 11 sq km in area, and secondly the basin of Aoufour in the east which is slightly larger with an area of 14 sq km. These basins were forned by the Cenomanian transgression onto the primary land surface at Sirwa.

The Cenomanian sequence which encases the manganese mineralisation has the following sequence going from the base upwards:

1. A lower detrital series formed of alternating sandstone and red clay which increases in thickness as one goes from west to east, which goes from just a few meters thick at Tasdremt up to a thickness of 30 m at Aoufour.
2. A dolomitic series consisting of banks of white to beige dolomites, once again the sequence thickens from 5 to 10 m at Tasdremt in the west, being upto 20 to 25 m thick at Aoufour in the east
3. An upper detrital sequence consisting of alternating sandstones and conglomerates.

The horizons that contain manganese mineralisation are associated with the dolomite series, the basal manganese horizon (layer No. 1) has an irregular base at Tasdremt, with a maximum thickness of 20 cm. The middle mineralised horizon (layer No. 2) is several times thicker, averaging 60 cm at Tasdremt and 50 cm at Aoufour. Layer No. 3 occurs at irregular levels at Tasdremt and is related to the upper dolomitic episode in the series, which itself lies some ten meters or so above the principal layer.

The mineralization is related to the principal dolomitic episode of the middle detrital Cenomanian. The manganese mineralization in the three sedimentary layers is similar to that observed at the Imini mine, but with smaller reserves, a relatively lower manganese content and a higher lead content.

The mineralization consists of lead bearing psilomelane (barium manganese oxide) with needles of coronadite (lead manganese oxide). The ore has an earthy texture with associated manganese wad and concretions containing lead bearing psilomelane, however pyrolusite is only rarely observed.

The considerable extent of the Tasdremt Aoufour manganese district indicates the potential for the presence of larger irregular manganese and lead mineralisation. Exploration carried out by SACEM in the Tasdremt district, between 1974 and 1976, produced an estimated historical resource of 270,000 tonnes of material, grading at an average of 43% Mn and 6% Pb.