Uranium exploration began in Algeria in 1969. The Precambrian shield of the Hoggar and its Tassilian sedimentary cover were considered to provide a geological environment favourable for uranium mineralisation. Initial exploration, carried out by means of ground radiometric surveys, found several radioactive anomalies (Timgaouine, Abankor and Tinef). In 1971, an aerial radiometric survey was performed over the entire country, an area of 2 380 000 km2. After evaluation of the data from that survey, several prospecting teams were involved in ground follow-up and in verifying anomalies. This led to the discovery of a large number of promising areas for further uranium exploration: Eglab, Ougarta, and southern Tassili (Tin-Seririne basin) where the Tahaggart deposit was discovered. Follow up of the aerial radiometric survey also led to identification of the Tamart-N-Iblis and Timouzeline sectors as areas for future uranium exploration. At the same time, the search for uranium entered a phase (1973-1981), which focused primarily on evaluation of the deposits already discovered. A second phase (1984-1987) was characterised by a marked slowdown in the search effort; however, investigations of the flanks of the known deposits and in neighbouring regions revealed other potential mineralised areas (e.g. Tesnou zone in the northwest and north Timgaouine). In Tin-Seririne basin (Tassili south of the Hoggar), geological mapping has resulted in characterisation of the distribution of uranium mineral deposits in the Paleozoic sedimentary sequences.