In modern practice of hydrotransport of ore, concentrate and slurry slurries the most common are centrifugal sand pumps and dredgers with open or closed impellers. As is known, in this type of pump, the entire flow passes through the impeller and the head is increased by the operation of centrifugal forces.

The Estonian oil shale deposit is characterized by large water inflows reaching 6000-8000 m3 / hour in spring floods (e.g. at the Käva II mine in April 1955). The geodetic height of water rise is small: 20-40 m - for the main drainage and 3- 4,5 m - for the area pumping.