Modern submersible pumps are high performance aggregates for long-term operation, which find application in open pit mining. Dewatering of groundwater to run an open pit mine with various conditions for submersible pumps often leads to short-term performance based on different circumstances in the well as well as in the general operation. These result in high maintenance and energy costs and decreases the drawdown in open-pit mining.

To ensure a long-time performance, a proper selection of submersible pump and motor is required. The adaption of the pump curve through variations of the impellers and the usage of variable speed drives to fit the system characteristics is an essential part to reduce energy consumption and obtain long-time performance. The frequency range of the aggregate by usage of variable speed drives has to be accurately defined, since it directly affects the choice of a submersible motor to avoid operation in over load and to prevent damage in the hydrodynamic bearings of the aggregate.

Another important aspect in picking the correct hydraulic for the dewatering process are the varying conditions in different wells. Different wells with various aquifers require the same long-term operation of a submersible motor pump. Many wells are fitted with several filters in different depths to reduce manufacturing costs. More than one aquifer supplies the well, which leads to different amounts of iron oxide as well as sand in the groundwater. Iron oxide and sand are the reason for clogging and erosion of the aggregate, which can be reduced through different countermeasures. The various filters may lead to a poor flow around the aggregate, which damages the motor through of a lack of heat transfer.

This paper shows guidelines for long-term operation of high performance submersible pumps due to the conditions of the mining industry.  Therefore, a holistic consideration of the aggregate and well takes place to receive guidelines, which minimize the rate of pump failures and increase the efficiency of the dewatering process. These recommendations include the proper selection of pump and motor, the correct usage of variable speed drives, as well as the adaptation of the head curve regarding different operating points depending on the specific well. Furthermore, this paper recommends different methods to prevent clogging and erosion through particles in the well.  These guidelines are linked to the research of different submersible motor pumps from various manufacturers in different wells in German open pit mines with short-term operation caused by several circumstances.


Guidelines for Long-Term Operation of High Performance Submersible Motor Pumps in Mine Dewatering

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
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Fluids Engineering Division Summer Meeting
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