Abstract: This study aims to examine the characteristics and volume of ex-coal mining pools that have been filled with water in the form of voids using River Surveyor M9 technology. The results of the void profile study become important data in planning a water management system which includes draining the pond with a pumping planning system and planning a sludge pond. From the results of a void study in Pit E, it was found that the area of pit E is 27.25 Ha, a depth of 57 m, a length of 820 m, a width of 205 m, and a volume of 6,479,241.5 m3.