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Introduction
The Vertimill® is a unique product offered exclusively
by Metso that has a long history in the metallic mining
industry. The technology was originally developed in
the 1950’s in Japan. In 1979, Metso Grinding division
(then Koppers) acquired the license for the technology.
During that time, Metso was successful at operating the
mills in their first large scale metallic operations, but we
found the unit had many mechanical short comings with
its original design. It was originally intended for industrial
mineral applications and was not robust enough to meet
the demands of the metallic mining industry. The machine
was redesigned to improve grinding efficiency, minimize
maintenance and down time, and maximize wear life -
the Vertimill® was born. In the twenty years since the
Vertimill®’s development, it has built the largest installed
base of any stirred milling technology.
The Vertimill®, available in standard sizes from 20 – 3000
HP (15 – 2240 kW), has a relatively large practical operating
range, handling feed sizes from 6 mm and grinding to sub 20
microns products. The capacity of the machine is relative
to the required power input for the intended grind, but mills
have been operated with throughputs exceeding 500 mtph.
Vertimills® are primarily selected because
of the operational cost savings they have
over other grinding mills. The total cost
of ownership for a Vertimill® is almost
always significantly less than a traditional
horizontal ball mill solution. The Vertimills®
advantages include:
• Reduced energy consumption
• Reduced media consumption
• Reduced Maintenance due to
machine simplicity
• Lower Installation Cost
• Less floor space
• High Availability
• Long Wear Life
• Quiet operation (less than
85 db possible)
• Greater operational safety
The most significant of
these advantages in terms of total cost of
ownership are energy consumption and
grinding media consumption (which is
directly related to energy consumption).
Issue 04 | 2010
TRANSFER OF TECHNOLOGY
Mechanically, the Vertimill® is a very simple machine with
an agitating screw suspended into the grinding chamber,
supported by spherical roller bearings, and driven by a
fixed speed motor through a planetary gearbox. The Figure
1 shows the Vertimill in its standard arrangement with all
of its major components.
Operating conditions of the Vertimill
The majority of Vertimill® copper grinding installations
are in Chile and most are in concentrate regrind applications.
Of the entire Vertimill® population worldwide, 85% by
power are in regrind applications. Historically, copper
regrind applications require products of approximately 35
microns. For products finer than this, fluidized stirred mills
would be another option, but many operations don’t yet
grind that fine with copper concentrate.
Fig. 1:
The Metso Vertimill®
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