The earliest mention of Taoudenni is by al-Sadi, in his
Tarikh al-Sudan, who wrote that in 1586 when Moroccan forces attacked the salt mining center of
Taghaza (150 km north west of Taoudenni) some of the miners moved to 'Tawdani'. In 1906, the French soldier Édouard Cortier visited Taoudenni with a unit of the camel corps (
méharistes) and published the first description of the mines. At the time, the only building was the
Ksar de Smida, which had a surrounding wall with a single small entrance on the western side. The ruins of the ksar are 600 m north of the prison building. The Taoudenni mines are located on the bed of an ancient
salt lake. The miners use crude axes to dig pits, which usually measure 5 m by 5 m with a depth of 4 m. The miners first remove 1.5 m of red clay overburden, then several layers of poor quality salt before reaching three layers of high quality salt. The salt is cut into irregular slabs that are around 110 cm x 45 cm by 5 cm in thickness and weigh around 30 kg. Two of the high quality layers are of sufficient thickness to be split in half, so that 5 slabs can be produced from the three layers. Having removed the salt from the base area of the pit, the miners excavate horizontally to create galleries from which additional slabs can be obtained. As each pit is exhausted another is dug, so there are now thousands of pits spread over a wide area. Over the centuries salt has been extracted from three distinct areas of the depression, with each successive area located further to the south west. The three areas can be seen clearly on satellite photographs. At the time of Édouard Cortier's visit in 1906 the mining area was 3 km south of the ksar; in the 1950s, the active mines were located in an area 5 km from the ksar, while the current mines are at a distance of 9 km. In 2007-2008, there were around 350 teams of miners, with each team usually consisting of an experienced miner with 2 labourers, giving a total of around 1,000 men. The men live in primitive huts constructed from blocks of inferior quality salt and work at the mines from October to April, avoiding the hottest months of the year, when only about 10 of them remain. The slabs are transported across the desert via the oasis of
Araouane to
Timbuktu. In the past, they were always carried by camel, but recently some of the salt has been moved by four-wheel drive trucks. By camel the journey to Timbuktu takes around three weeks, with each camel carrying either four or five slabs. The typical arrangement is that for each four slabs transported to Timbuktu, one is for the miners and the other three are payment for the camel owners. Up to the middle of the 20th century, the salt was transported in two large camel caravans (
azalaï), one leaving Timbuktu in early November and a second leaving Timbuktu in late March, at the end of the season. Horace Miner, an American anthropologist who spent seven months in the town, estimated that in 1939-40, the winter caravan consisted of more than 4,000 camels and that the total production amounted to 35,000 slabs of salt. Jean Clauzel records that the number of slabs reaching Timbuktu increased from 10,515 in 1926 to 160,000 (4800 t) in 1957–1958. However, in the early 1970s the production decreased, and at the end of the decade was between 50,000 and 70,000 slabs. ==Prison==