Modern Mining June 2015

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PRODUCT News
June 2015MODERN MINING55
Having delivered an impressive perfor-
mance in several overseas applications,
Sandvik CR810 hybrid roll crushers are
now starting to prove themselves in the
African mining environment. A recent two-
year study conducted at Genet Mineral
Processing’s Onverdacht colliery near
Belfast in Mpumalanga has demonstrated
that even extremely hard South African
coal can be crushed in a primary or sec-
ondary application at a cost as low as 55
cents per ton.
Sandvik CR810 hybrid roll crushers
store kinetic energy in the mounted fly-
wheels (belt drive models) and the fast
running fly wheels (direct drive models).
A flywheel located on each roller delivers
a crushing power up to four times that of
a crusher without any flywheel, increasing
the capacity and improving the maximum
material hardness by nearly 65 %. This
enables the machine to crush large lumps
and maintain a stable crushing process
even during peak conditions.
“The Sandvik CR810 has proved ideal for
primary and secondary crushing of materi-
als that are soft to medium-hard, as well as
wet and sticky,”says Sandvik Mining’s Colin
Jones, Crushing and Screening Division,
Region Africa. “Its compact design less-
ens the required installation footprint
and it utilises roller teeth with a large gap,
allowing it to produce high quality output
products with very low fines.
“The teeth are installed in a line, instead
of the conventional scroll pattern, at 120
degrees, which allows greater penetration
into the crusher. The teeth are also inter-
laced for bending and shearing, with a
lower tooth that delivers compaction. The
end result is a cubical product. Scrappers
are fitted to keep the teeth clean and there
is no other crusher in the world that has
this feature.”
Depending on the application and
model, Sandvik crushers of this type can
achieve capacities in a range of 100 up to
11 500 metric tons per hour (t/h) and can
be used in primary, secondary and tertiary
crushing applications.
“Sandvik hybrid crushing technology
was first tested on limestone and sand-
stone in Europe and continues to deliver
exceptional performance in these sectors
today,” Jones says. “Two years ago, when
sample analysis of the coal being mined at
Flowmeter is a ‘plug and play’ solution
With no cables or other parts protruding past the flanges, compact dimensions and a low
weight, the UFM 3030 flowmeter from KROHNE is very easy to handle.
The outer casing of the UFM 3030 is an all metal con-
struction and there is therefore little risk of damage to
the flowmeter during the installation process.
The flowmeter is delivered ready to measure.
Once mechanically and electrically connected, the
unit does not require any specific handling such as
fitting sensitive transducer parts or making specific
cable connections. In case of a remote installation, a
cable with pre-fitted connectors is provided. In this
way the signal connections are easily made without
the need for special handling. The cable length can
be selected from 5 up to 100 m.
KROHNE, tel (+27 11) 314-1391
Hybrid roll crusher proves itself at SA colliery
Onverdacht colliery indicated a hardness
of 70 MPa, with the surrounding sand-
stone at 150 MPa, we recommended this
machine to management and began a test
programme on the mine.”
The Onverdacht roll crushing plant has
a capacity of 250 t/h with a static grizzly
on the feed bin and the bars set 400 mm
apart. Considering that the third dimen-
sion was approximately 500 mm, the
machine selected was the Hybrid CR810/
08–10. This model incorporates rolls
800 mm in diameter and 1 000 mm long,
and features rapid tramp metal release,
self-cleaning of wet and sticky material
and three dimensional crushing using a
kinetic energy input.
The machine was put into service in
January 2013 with a gap setting of 100 mm
where 90 % of the feed material passed.
Shortly after the plant was commis-
sioned, it was decided to reduce this gap
to -75 mm to help the secondary crushers
produce a final product of P100 < 40 mm.
Roll speed is the same as material flow
speed, so there is no retention time.
In terms of maintenance and repair, in
August 2013 it was noted that the fixed
roll bearing was becoming hot. The bear-
ing was repaired and the crusher was
back in operation just four days later.
Subsequently, in October 2013, a loose
bolt was detected and the plant was shut
down for 12 hours to tighten all the other
bolts in the installation. Over the two-year
trial period, plant availability was 98,6 %.
“During the plant’s operation, power
consumptionwas measured periodically for
both motors at 108 kW,” Jones says. “With a
throughput of 250 t/h and using 60 cents
per kWh, we determined that the consump-
tion was 0,432 kWh, or 26 cents per ton.
“By October 2014 the plant had
produced about 1,5 Mt and the mine pur-
chased a complete set of wear segments
at a cost of R300 000. Based on the cost of
the entire spare and wear parts and power
consumption, it was possible to accurately
calculate an operating expenditure (OPEX)
figure of 55 cents per ton.”
Rory Power, Group Maintenance
Engineer at Genet Mineral Processing, says
the Sandvik hybrid crusher has proved to
generate fewer fines than previously expe-
rienced with other crusher configurations.
A second Sandvik CR810 hybrid roll
crusher is in operation in South Africa in a
chrome application and three are at work
in the DRC crushing copper ores and gold
oxides.
Sandvik Mining, tel (+27 11) 929-5400,
website:
The Sandvik CR810/ 08–10 hybrid roll crusher installed at
Onverdacht colliery near Belfast in Mpumalanga.