sentences:  The Saharan test sites were produced “in galleries”, those having been horizontally excavated in the Tan Afella on the site In Eker.This type of “shooting gallery” was dug to end in a spiral shape.On the one hand, this shape of tunnel seriously weakened the ground at this point, and on the other hand, it dampened the expulsion of gases, of dust, and of lava produced by the vitrification of the soil.