The conveyor belt system in the excavation area has two different types; that is, shifting and not shifting. The shifting conveyor belt system is equipped with rails (shifting rails). Before the shifting process, a new 5.2 meters-thick hardened foundation must be made first.

There are 3 (three) types of shifting, i.e. parallel, slewing and a combination of both. Parallel shifting moves by shifting the head to the tail of the conveyor, parallel to the previous position in a certain distance. Slewing shifting moves by shifting one end of the head or the tail for a certain distance while the other end remains in its original position. This would look like the shape of a swing. 
Combination shifting is combination of parallel and slewing shifting in a simultaneous time. This type of shifting is necessary to accommodate a considerable distance.

Source: ptba.co.id