Mining Institute of North-Eastern Federal University (Yakutsk, Russia):

Ovchinnikov N. P., Director, Candidate of Engineering Sciences, Associate Professor, ovchinnlar1986@mail.ru

Loss of gravel pump operability in a dense-medium unit (DMU) due to extensive hydroabrasive wear of the impeller is currently among the key causes for the screening plant downtime at the mines of «Almazy Anabara» JSC (Yakutia), reducing their diamondiferous sands washing output. It usually takes up to two hours to replace a broken pump with a backup unit. According to the calculations, each forced downtime of a screening plant due to a DMU gravel pump replacement can lead to losses of around one million rubles. In order to reduce this downtime, all gravel pumps at «Almazy Anabara» mines were additionally equipped with frequency converters, maintaining the operating pressure in the dense-medium hydrocyclone despite the gradual deterioration of the impeller due to attrition by the slurry solid phase. However, the converters prevent the complete utilization of the impeller service life in gravel pumps. At the time of decommissioning, the rpm of gravel pump electric motors exceeds the nominal values by 8–15 %. This variation is due to the lack of recommendations for the maximum possible increase in the number of revolutions. The purpose of this work is to substantiate a streamlined service life for DMU gravel pumps to enable more efficient utilization of the process equipment of screening plants at the mines of «Almazy Anabara» JSC.

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