Justification of the design and operating method of self-cleaning filters for downhole pumping units at mining operations

Widespread use of surface methods for mining of mineral deposits makes it necessary to increase the efficiency of the applied technologies and improve the equipment to reduce the groundwater level. Unfavorable hydrogeological conditions affect performance of the excavation, loading and hauling machines in open-pit and open-cut mines. One of the ways to control the groundwater level is to drill dewatering holes equipped with downhole electric centrifugal pumps. A considerable content of mechanical impurities in the pumped borehole fluids, i.e. the hydroabrasive mixture, makes it necessary to use downhole pumps in a wear-resistant design fitted with inlet filters. Clogging of the filters due to deposition of mechanical particles on the filter surfaces causes failures of the downhole pumping units and requires performing tripping operations to regenerate and restore the permeability of the filter elements. The article provides basic information about the design of dewatering holes. It describes the specific features of the hydroabrasive wear process in the working sections of the electric centrifugal downhole pumps. Technical solutions are justified for the design of self-cleaning filter and tubing string extension piece of downhole pumping unit. It is shown that due to the reciprocating movement of the downhole pumping equipment inside the dewatering hole it is possible to utilize the elastic deformation of the filter element inside the inlet filter of the pumping unit. When deformation of the filter element takes pace and the size of slots, which allow the liquid to pass through, changes, mechanical depositions on the surface of the filter element are destroyed, which makes it possible to restore its permeability and performance. The technical solutions proposed in the article can also be used at mines that use underground mining methods to produce potash, apatite-nepheline ores, as well as ores of ferrous and non-ferrous metals and other minerals. they are best employed during construction and upgrading of their surface facilities located in areas with high groundwater levels. In addition, these technical solutions may be relevant for the pumping equipment used in fluid mining.