2018
COMMINUTION
Steve Morrell
r Steve Morrell is a minerals processing
engineer with over 30 years of specialist
experience in the resources industry. He
has been involved in the circuit design of the
majority of major comminution circuits
internationally, through which he has
established himself as a world leading expert in
comminution design and optimisation.
Morrell joined the JKMRC as a Master’s
student some30 years ago. His project was to
extend the AG/SAG mathematical model
developed by Kam Leung. However Steve’s
project had an additional challenge. A big part
of his project was to measure and size a SAG
mill load at the sponsor site. The sponsor site
was ALCOA. The mill was fed with bauxite and
the process liquor was hot caustic soda.
When Steve carried out this task with
enthusiasm and skill and without complaint, the
old hands at the JKMRC formed a view that
Steve would go far in the world of SAG milling.
Steve continued to a PhD in which he aspired to
answer all of the relevant SAG questions
ie modelling, ore characterisation, power,
dynamics etc. However these ambitions would
comprise at least five doctoral projects. After
extended debate, he concentrated on
measurement and prediction of AG/SAG power
mill draw. This was a highly contentious issue at
the time. Steve’s project converted power
measurement and prediction for AG/SAG mills
into “business as usual” and the power model
was incorporated into JKSimMet. He also
developed the Variable Rates SAG mill model
which is still standard in JKSimMet. Steve was a
member of the project team which received the
Aus IMM Operations Mineral Industry Operating
Technique Award for the development of
JKSimMet.
While Steve was working on his PhD he
succeeded Tim Napier-Munn as leader of the
long running AMIRA P9 project. During his
leadership of P9, Steve and his team made
major contributions to comminution,
classification and even to liberation as part of
the CMTE Fine Grinding project.
After contributing to the JKMRC Blue Book
“Mineral Comminution Circuits – Their
Operation and Optimisation”, Steve became co-
leader of the AMIRA Mine to Mill project with
Andrew Scott. This allowed his ideas in
comminution to be extended towards the pit
and to work with Andrew to quantify the many
synergies which become available when
blasting is considered to be the first stage of
comminution. The industry adopted their ideas
D
HoF 10 International Mining | JUNE 2019 Supplement
in record time (AusIMM Mine to Mill Conference,
1998). The more astute mining companies make
good use of these ideas to this day.
Steve was also a member of the project team
which received the Aus IMM Operations Mineral
Industry Operating Technique Award for the
AMIRA Mine to Mill project.
The Mine to Mill project also exposed the
need for better breakage characterisation
techniques which could be used on small
samples.
Now an independent consultant, Steve
worked to develop the SMC test. This test could
be used on drill cores to estimate the JK A*b
parameter. It was later adapted to small
samples of broken rock and is now a standard
test for what became known as Geometallurgy.
The AMIRA GEM projects have pursued
application of this strategy to other ore
properties with some degree of success. The
SMC test is licensed widely to laboratories with
JK Drop Weight Testers. Steve was also the co-
developer (with Doug Brown) of the JKMRC Drop
Weight Tester.
Steve also supervised the development of a
JKMRC mathematical model of the High
Pressure Grinding Roll. This model is also
included in the JKSimMet and has enjoyed
broad success and model development is
ongoing.
During the years from 2000 to 2010, Steve
was a highly successful, independent consultant
who was well respected by both operators and
equipment suppliers. I doubt there are any
major AG/SAG installations that he has not
been asked to review or to assist with mill
selection.
In 2003, based on his extensive practical and
research-based experience, Steve founded SMC
Testing Pty Ltd to license the innovative SMC
Test ® – a laboratory comminution test which
provides a range of information on the breakage
characteristics of rock samples for use in the
mining/minerals processing industry. The SMC
Test is one of the most useful, versatile and
cost-effective rock breakage test procedures
available.
Since its inception in 2004, SMC Testing has
conducted over 35,000 SMC Tests on behalf of
the majority of the world's
mining companies. These
tests cover over 1,000
different orebodies across
80 countries and constitute
one of the largest data
bases of its kind in the
world. The SMC Test, unlike
any other comminution test available on the
market, enables both power-based calculations
and simulation studies to be conducted. It has
been proven through benchmarking against an
unprecedented 120 processing plants around
the world, covering just about every type of
comminution circuit in operation, including the
largest to the smallest equipment available on
the market, and treating some of the softest to
the hardest ores that have been discovered to
date. This enables the SMC Test ® to provide
unparalleled versatility, precision and accuracy
compared to other alternatives.
In 2016, the Global Mining Standards and
Guidelines Group (GMSG) recognised the SMC
Test through the publication of its guideline
“Morrell method for determining comminution
circuit specific energy and assessing energy
utilization e ciency of existing circuits”.
The guideline describes the “Morrell”
approach for predicting the specific energy
requirements of conventional crushing, High
Pressure Grinding Rolls and tumbling mill
circuits through the use of the SMC Test as well
as how to assess the energy utilisation
efficiency of existing comminution circuits. As
Barrick Gold reported, this methodology was
one of the key technologies employed by them
in a program started in 2008.
This program lead to significant savings at a
number of Barrick’s operations which have been
quoted as follows:
“Results have been very positive with more
than 20% net grinding energy improvement in
one case. These actions have lead to more than
43,000 t/y reduction in CO 2 emissions in the
three operations reviewed.
“Relative to Barrick’s total “carbon footprint”,
this represents a net efficiency improvement of
almost 1% and supports one of the key pillars of
Barrick’s climate change standard. Overall the
three sites reviewed have reduced energy
consumption by about 61 million kWh per year
in relative terms. This cost saving of about
$5 million per year has been further augmented
with more than 200 combined tonnes per hour
of throughput providing in the order of 60,000
ounces of gold annually.”
Dr Steve Morrell was given a lifetime
achievement award at the SAG Conference in
September 2011 and the Art MacPherson Award
for 2011 by the Canadian Mineral Processors
Society of CIM.