Reliable grinding operations with GMD and RMDs

Powerful and advanced grinding circuit supporting productivity at Mount Milligan mine

When it comes to productivity at remote mine sites, highly reliable and robust grinding equipment and a good service partner are a must. 

Mount Milligan mine
Mount Milligan is a new copper and gold project, located some 1,000 km north of Vancouver in central British Columbia, Canada. First concentrate was shipped in September 2013 and it is projected to process 60,000 metric tons of copper ore per day over a 22-year operating life. Mount Milligan is owned and operated by Thompson Creek Metals Company, a North American mining company that took over mine operations through its acquisition of Terrane Metals Corporation in 2010. 

  • Variable ore qualities throughout the ore deposit (including very hard rock) 
  • Managing high process capacity 
  • Remote location 
  • Extreme environmental conditions (challenging access road, varying temperature

Our solution 
Early project involvement with consultancy and technical expertise to support Terrane Metals was key in developing the best fit of drive solutions for the site's requirements. As a result, ABB could provide a fully integrated and optimized solution for the entire grinding circuit consisting of:

  • 1 x 23.5 MW gearless mill drive system (GMD) to power the 40 ft SAG mill 
  • 2 x 13 MW low-speed dual pinion ring-geared mill drive systems (RMD) to power the plant's 26 ft ball mills

Both drive solutions share many common operation and maintenance features such as frozen charge protection, frozen charge remover, controlled rollback, automatic positioning and creeping and variable-speed, that allow for flexible and reliable grinding operations. To further simplify operations and maintenance of the machines on-site and to reduce the amount of engineering documentation both drive solutions were standardized by using the same type of equipment wherever possible.  

The logistical challenge of transporting the large GMD stator to site via the unpaved access road, was solved through a design change in the stator. Normally engineered and designed to be transported in 4 pieces, this stator was engineered in 5. Thus reducing the size and weight of each individual piece. Each stator piece was also equipped with a special heating system to handle temperatures of up to -40°C during transport. 

The full scope of ABB delivery includes consultancy, design, engineering, installation supervision and commissioning of all three drive systems as well as a comprehensive service contract. All equipment is certified for use in Canada by the Canadian Standards Association (CSA).

Protecting the assets 
A service contract covering the full scope of ABB equipment, including remote diagnostics, quarterly reports and regular on-site visits by ABB service engineers for preventive maintenance purposes are part of the agreement in addition to a regular on-site ABB service engineer who supports 24/7. 



Main data


Mount Milligan / Thompson Creek Metals 


British Columbia, Canada

Customer need: 

Highly reliable and powerful grinding circuit to handle high process capacity and challenging ore characteristics



SAG mill
Ball mills

Customer benefits:
Commissioning year: 2014

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