Dewatering wells in open cast mining

In open cast mining, the groundwater levels must be continuously reduced to protect the mining area from flooding and the excavation walls from instability due to water pressure. A large number of dewatering wells with submersible pumps are kept in operation for this purpose. A continuous water flow prevents the pump shaft from blocking due to the effects of hardening clay/iron oxide deposits. To regulate the pump output, precise level measurement is required in each of the up to 750 m deep wells.