Reexcavation

the repeated excavation of rock, done in open-pit mining of mineral deposits and during earth moving in construction. Excavators, usually draglines, and single-bucket loaders are used. Reexcavation is often done in surface mines with complex flow sheets, where stripped overburden is reloaded into the area already worked. In these cases the insufficient working dimensions of the stripping excavator cause the stripped debris to partially or completely fall back onto the extraction bench. To clear the bench and increase the area of the work face, a pit dump excavator reexcavates part of the rock from the initial pile. The ratio of the reexcavated rock to the total amount initially excavated is called the reexcavation factor, or the factor of repeated dumping. The reexcavation factor is usually 0.5–1.