Iron ore mining plays an important role in the economy of Mauritania. Banded iron formations with 64% iron hematite lenses were discovered at F'Derik-Segazou, Tazadit hills and Rouessa, close to the border with Western Sahara in the 1970s. Mining began 25 kilometers north of Zouerate, as part of the Guelb project in the mid-1980s. The site has itabirite with 37% iron. Dust storms and problems at the site's mill have limited production. A different Guelb project site 12 kilometers east of El Rhein became active in the early 1990s, extracting 64% iron ore. A Neoproterozoic carbonate unit, part of a synformal nappe overturned in the Paleozoic, now forms a major copper deposit 250 kilometers northeast of Nouakchott in the Mauritanides Belt. The one kilometer, 250 meter wide deposit spans the West and East Moghrein Guelb hills.
