Designed for hard rock grinding mill applications


The UMD pump is designed specifically to handle the exceptionally abrasive discharge slurries that flow from hard rock grinding mills. It’s heavy-duty design features a unique unlined casing design, optimized impeller, and oversized liners, as well as our unique wear ring assembly:


  • A large clearance around the impeller creates a deep bed of slurry between the impeller and casing, which acts as a buffer and shields the casing from direct impact of coarse solids. In addition, a large cutwater reduces turbulence to extend pump life.  
  • The shape of the pumping vanes has been optimised with increased shroud diameter and improved expelling vanes. This advanced design limits localised wear on the leading edges to maintain pumping efficiency and extend wear life.  
  • Oversized suction and backliners – which are available in a range of materials – protect the sides of the casing from wear due to turbulence.  
  • The unlined casing design reduces space requirements, as well as maintenance time (by at least 20%) and costs (as fewer components are required). The symmetrical design means that the same casing, suction and backliners, and wear ring can be used for both left- and right-handed orientations, reducing inventory requirements. 

Suction-side sealing wear ring technology

KREBS millMAX wear ring technology is in all of our centrifugal slurry pumps. It eliminates grinding, improves efficiency and extends life of the impeller.

The UMD slurry pump benefits 


These design features deliver multiple benefits, including even and predictable wear for wet end parts and a 5% to 10% reduction in power consumption for the same head and flow. As a result, the UMD pump has been proven to reduce downtime, power, and maintenance costs when compared to conventional pump designs, and achieve lower cost-per-ton pumped. 


The UMD pump is available in a range of interchangeable elastomer, alloy, and polyurethane liner materials and can handle flow rates of 200 GPM to 90,000 GPM (50-20,000m3/hr).


Versatile Options: UMD-R and UMD-HP


In addition to the standard UMD pump, two alternate designs are available to meet specific application requirements: the UMD-R rubber-lined split-case pump and UMD-HP high-pressure pump. 


UMD-R split-case rubber-lined pump


The UMD-R pump features a fully rubber-lined split-case design that is particularly suited to heavy-duty mill discharge applications where wide flow rates and/or corrosive agents are an issue. The thick rubber liners are available in a range of elastomer material options.


The UMD-R pumps utilises the same suction liner assembly, impeller and back liner components as the UMD unlined pump range.


UMD-HP: Handling high-pressure coarse tailings and hydrotransport


The UMD-HP pump is available for multi-stage, high-pressure coarse tailings and hydrotransport applications and features tie-bolt outer casing halves within which sits a large-diameter impeller. A thick chrome-iron casing with additional ribs supports the back and suction liners, which are available in a range of ultra wear-resistant materials for extended wear life in even the most abrasive applications.


Wear life extension: UMD pump success story


Demonstrating the advantages of the standard UMD design, a UMD pump was installed at a gold mine in Indonesia, which was looking to improve performance of its ball mill in the concentrator of a cyclone feed application. The facility processes 240,000 tons of ore per day and required frequent shutdowns to maintain performance.


A UMD 26x22 (650 x 550mm) was installed at the ball mill, with different suction liner and wear ring material combinations tested. After two trials, the new pump had already shown significantly extended wear life, with two different suction liner assemblies hitting the targeted wear life. The first more than doubled wear life compared the competitor; the second hit three times the wear life. The casing and impeller remained unchanged throughout both trials with the impeller now running more than 2.5 times longer than the competitor.

Did you enjoy this article?

Check out our other blogs and continue the journey through the world of centrifugal slurry pumps.

Blog | Selecting a slurry pump for mining and minerals processing applications. 

Blog | Split-case slurry pumps: KREBS® slurryMAX™. 

Blog | Setting the standard: KREBS® millMAX™. 

Blog | Avoid shearing and air locking: KREBS® hMAX™ pumps

Blog | A sump pump you can trust KREBS vMAX slurry pumps


You can also dive deeper and discover why KREBS pumps are the ideal choice for your slurry handling needs in the webinar. Or download the brochure and learn more about our innovative UMD pumps. For further information on how our reliable slurry pump parts can extend your pump's lifetime, feel free to contact us.