Spotlight Feature Articles ME Elecmetal Comminution March 16 | Page 9

COMMINUTION
transmit twice as much power in the past. We
have simply rearranged the dual system into a
quad system that equally divides input power
from two load-sharing motors into four pinions.
With this architecture, the Metso QdX4 drive is
capable of delivering up to 32 MW in horizontal
mill comminution.”
This drive system has many features that help
achieve both time and cost efficiencies from an
equipment point of view and in terms of the
overall costs in a large-scale project. For
example, two installed QdX4 drive units weigh
less than one GMD quarter section. This
significantly reduces transportation cost, delivery
time, equipment handling, and site preparation.
selection of materials for both components
(carbides and tyre base); and good HPGR process
control. “The most challenging period for wear
rates is normally the first months after
commissioning. During this period of operation
insufficient feed, frequent plant stops and lack of
operator’s experience add to wear issues. Early
activation of the HPGR automatic control loops is
always the highest priority as it assists in
elimination of human error.”
With good control of feed material and tramp
metal detection and removal, breakage of studs
can be minimised. During nearly 12,000 h (on
load hours) of operation the studded lining in a
test gold ore application (see graph) had less

late last year, a new drive system for grinding
mills. Over the past three years, Metso worked in
close collaboration with CMD and Ferry Capitain
to develop a new high-powered mill drive
solution for large SAG and ball mills. After
exhaustive design research that concluded with
the build, installation and continuous full-scale
testing operation, Metso introduced the Metso
QdX4™ Mill Drive System.
The system was tested for over 3 million cycles
at 28 MW (2 x 14 MW) with an input speed of 320
rpm, proving the torque splitting system
arrangement. In the past, grinding mills
operating between 18 MW and 28 MW required a

than 30 studs broken or chipped. All studded
lining repairs were carried out during planned
maintenance shut-downs. Maintenance repairs of

large electrical wrap-around motor – a Gearless
Mill Drive (GMD). The Metso QdX4 is an
alternative option to the GMD. Until now, the
gear-driven solution for large SAG and ball mills

the studded lining did not have any negative
impact on HPGR mechanical and process
availability. During an initial period of operation
higher wear rates were measured on the floating

was limited to 18 MW.
“Our goal was to design a robust, reliable,
cost-effective, high-powered mechanical solution
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