PT. Vale Indonesia is planning to conduct open-pit mining at the Petea location, which is situated upstream in the Lamunto watershed. Prior to the mining activities, measures need to be taken to prevent any harm and damage to the surrounding environment, especially with regard to soil erosion, which could potentially impact the Lamunto watershed, as it serves as the outlet for the mining location. The USLE (Universal Soil Loss Equation) method, aided by the ArcGIS application, was used to analyze the potential erosion that could occur. Additionally, the sedimentation rate was calculated using the SDR (Sediment Delivery Ratio) equation, based on the erosion rate and the area of the mining plan, in order to plan for sediment storage tanks, or sumps. The results of the study revealed that the sediment potential for sumps A, B, C, D, E, F, G, and H was 550.39 m3/year, 1195.31 m3/year, 1588.43 m3/year, 1908.27 m3/year, 2423.33 m3/year, 1899.53 m3/year, 1941.76 m3/year, 2169.15 m3/year, and 2756.29 m3/year, respectively. The slope factor (LS) was found to be more influential than the catchment area in calculating sediment potential, as evidenced by the greater sediment potential in sump D compared to sump F.