Manganese-Iron

Manganese- iron depos its OCCUI ' as lens- shaped, concordant bodi es and fissure fillings in the Carboniferous Um Bugma Formation east of Abu Zeima and Abu Hudeis. The ore lenses average 2 meters in thickness, but locally achieve a thickness of 4 meters. The host rock consists of  red and yellow crystalline dolomite, variegated  shale, and Sandy clay. An average lens might contain 10,000 tons   of  ore  above 2 a Cutoff of 20 percent manganese.

The mineralization consists of manganese oxides mixed with iron oxides; earthy oxides and pyrolusite are associated with goethite hematite and other minerals such as calcite. Traces of uranium and copper accompany the manganese. Ore specimens with up to 60 percent manganese occur in the deposits; historically mined, hand-sorted, high-grade material from the Umm Bugma district averages up to 40 percent manganese. Remaining explored deposits of significant tonnage average between 20 and 30 percent manganese.