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PROJECT: Repair and refurbishment of an RH120E carbody

PROJECT: Repair and refurbishment of an RH120E carbody

CLIENT: Advanced Group Services 


Based in the North East of England, Advanced Group Services – a leading manufacturer and repair and refurbishment specialist of mining equipment and heat exchangers – commissioned Miller to provide an overhaul of a Caterpillar 6030/O&K RH120E carbody on behalf of one of its customers.

Carrying out NDT methods, Miller identified repair requirements, and further conducted these in only a matter of two weeks.


Advanced Group Services required the carbody of a Caterpillar 6030/O&K RH120E to be repaired on behalf of one of its customers located in Saudi Arabia. The machine had been in heavy use for many years and required maintenance to increase productivity and prolong the lifespan of the machine itself.


  • Miller has supported Advanced Group Services over a number of years to deliver repairs and refurbishments on an array of heavy equipment;
  • Over 45 years’ experience in manufacturing, repairing and refurbishing an extensive range of earthmoving & heavy mining equipment;
  • Dedicated repair and refurbishment facilities spanning over an impressive 16,950 sq ft;
  • Overhead craneage facilities with high crane lift capabilities of up to 32 Tonne
  • Specialist equipment including line boring capability to guarantee precision;
  • Highly trained and skilled team comprising specialist skillsets in fabrication, welding, NDT, fitting and line boring;
  • Ability to tailor repair services to individual customer needs to provide a bespoke package
  • Dedicated transport facilities for heavy equipment and machinery;
  • Work Safe with Miller initiative embedded in the culture at Miller ensures a sustainable safety mindset is instilled with individuals at all levels.


An initial inspection was carried out by Miller to fully determine the works required. This included performing a dye penetrant inspection – a Non-Destructive Testing (NDT) testing method – to establish any surface flaws by capillary action on the RH120E carbody once all the welds had been shotblast. This type of non-invasive inspection allowed Miller to accurately locate all types of surface defects.

Once the report once conducted with areas of damage identified, Miller delivered:

  • Welding repairs to defective welds;
  • Re-welded and feather welded high stress points on external frame corners;
  • Build up wear on frame topside caused by tracks;
  • Checked threads on slew ring holes and tapped as required;
  • Repaint of the carbody to the original OEM colours.


  • Miller identified a number of structural failures across several areas of the track frame through invasive and comprehensive testing methods;
  • These failures were fully repaired with the structural integrity of the carbody fully restored to withstand the intended load;
  • Miller delivered a cost-effective repair in only three weeks which will significantly prolong the life of the RH120E Track Frame eliminating the cost of new equipment.

“We are always greatly impressed by Miller’s ability to bring equipment back to life. We have worked with the company for many years, and will continue to do so, as they always deliver a top-class quality job, with a very quick turnaround.”

Philip Riches, Owner at Advanced Group Services

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