1 Chapter II Literature Review II.1 Problem Exploration After understanding the background of this research, the theoretical foundation is needed to answer the research question and objective. As this thesis aims to understand user acceptance of normalisation in sediment pond methods, in this chapter, the researcher provides theories that are needed to support this research. The current method of normalising the sludge in the sediment pond is the conventional method of using dump truck units and excavators to dredge the sludge (Figure 12). This method is less effective because it requires a relatively large amount of material for blending, requires a large number of dump truck units, normalisation activities cannot be carried out in rainy weather, and has a high safety risk because heavy equipment units work near the mud area. This method also requires a lot of fuel for the heavy equipment units, resulting in high costs. The best alternative method is needed so that normalisation activities become more effective by not requiring material for blending, and not requiring heavy equipment units such as dump trucks and excavators because they can be replaced with a pipe system. And normalisation activities with this method can still be carried out continuously despite rainy conditions and have a lower potential safety risk because it does not involve a lot of interaction between dump truck units and manpower. This alternative method is more cost-efficient because it eliminates material costs for blending and fuel costs for dump truck units. A schematic comparison of how the existing method works with the alternative can be seen in Figures II.1 and II.2. 2 Figure II.1 Schematic of the Current Normalisation Method (Source: Internal Report Data of PT. BIB) Figure II.2 Schematic of Geotextile tube & Geotextile pool Normalisation Method (Source: Internal Report Data of PT. BIB) II.2 Literature Review II.2.1 Sediment Pond A sediment pond is a pond made to accommodate and settle runoff water particles originating from mining sites or temporary material stockpiles before the water is discharged into the river body. The function of the settling pond is to settle mud or solid material from mine water before it flows into public waters and as a place to control water quality before it flows out of the settling pond (Kepmen ESDM 1827 K/30/MEM, 2018). II.2.2 Normalisation of Sediment Pond Sludge 3 Normalisation of sediment ponds is the maintenance of storage ponds and draining of settling ponds (Kepmen ESDM 1827 K/30/MEM, 2018). Maintenance of the settling pond needs to be done to prevent silting. Maintenance efforts need to be carried out regularly by dredging sediment material at the bottom of the settling pond using a truck unit. Dredging is carried out when the amount of sediment is around 60% of the design volume of sediment to maintain optimum deposition (Sianturi P, Yusuf M & Iskandar H, 2019). The composition of the tools that support pond normalisation activities to achieve the target using excavators and dump trucks, with the number of dump trucks adjusted to the needs so that there is no waiting time for excavators (match factor) and speed up the normalisation process (Maulana, I & Heri P, 2021). Mud normalisation activities in sediment ponds with conventional methods using trucks can be seen in Figure II.3. Figure II.3 Mud Normalisation Activities in Sediment Ponds with Conventional Method (Source: Internal Report Data of PT.