Man-made dumps at a site present various concerns owing to the variability of the water table within it, which can destabilize the dump. The study focused on the waste dump at the open-cast mine site, which can be as high as 90 m and primarily consists of a combination of overburdened soil and rock. Based on a geotechnical investigation, the strata beneath the dump were clayey up to 10–15 m thick. An experimental investigation of the waste dump sample was conducted to determine the shear strength parameters. The probabilistic approach using the Monte Carlo simulation technique was utilized to perform the sensitivity analysis and determine the Factor of safety (FoS). The sensitivity study on water table variation was conducted with a variation of weak soil layer by varying the height of the dump. The study’s finding shows the stability variation with increasing dump height over weak soil strata with water table fluctuation. The results obtained were found to be consistent with the field.