Muara Tiga Besar Utara (MTBU) is one of the longest operating pits at PT Bukit Asam. Most of the pit area is a stockpile area. This is because the overburden material in the MTBU pit uses the backfilling method. So that the MTBU pits experience slope failure caused by infiltration of rainwater into the soil layer on the slopes which will increase the load on the slopes as a result of increased …