The lignite open pit mine of "Drmno", Mining Basin Kostolac, deals within the framework of the Electric Power Industry of Serbia. The imperative condition for coal exploitation in this deposit is closely connected to the protection of open pit mine against ground waters which is based on the complex, spatial and timely non-stationary system of about 200 drainage wells, having the total installed power of pumps of approximately 2 MW. This system pumps out approximately 15.000,000 m3 water annually. The already existing manner of monitoring and management of the work of wells neither supports in real time the guiding of the process of dewatering according to the optimum regime and enables precise monitoring of electric power consumption nor monitoring the capacity and time efficiency of the system and does not register and does not diagnosis stoppages. The system also fails to enable prognosis and preventive undertaking the corrective measures, monitoring the reliability work of system components, precise monitoring of operation costs, control of costs covering building and exploitation of the system, storage of experience, efficient end effective support to the decision-making process. Both these recognitions and the fact that each ton of the excavated coal is burdened by the costs of removal around 2.5 m3 water from the working environment, influenced the initiating the idea on introducing computer-supported monitoring-management system of a complex for dewatering of the "Drmno" open pit mine. .