MTU engines power machines at Modikwa Platinum Mine on South

Mining
MTU engines power machines at Modikwa Platinum Mine
on South Africa’s rich mineral reef
Who:Modikwa Platinum Mine
What:MTU Series 900 engines for drill rigs and load haul
dumpers to perform in the harshest conditions, at peak
performance rates
Why:MTU Series 900 engines‘ ability to perform optimally
with low fuel consumption, minimal downtime and with
built-in automated features to enhance component
forecasting
Where: Limpopo Province, South Africa
Africa
Underground mining demands extreme
performance for extreme periods, both for
miner and machine. In a 24/7 operation,
durability and efficiency are the building
blocks to profitability. At Modikwa Platinum
Mine, one of South Africa’s leading platinum
mines, you will find some machines which
perform Herculean feats in places that they
have very little right to be in. Up to 800m
underground in the mine, drill rigs and load
haul dumpers powered by MTU Series 900
engines, add significantly to Modikwa’s
profitability through their performance,
durability and efficiency. In terms of
performance it means minimal downtime,
fuel efficiency and low emissions.
Modikwa is located in South Africa‘s Limpopo
Province, situated less than 120km from the
world famous Kruger National Park. The region is
rich in platinum reserves. Modikwa is a joint
venture between African Rainbow Minerals and
Anglo Platinum and forms part of the Bushveld
Igneous Complex, spanning an area of 14,278ha.
The Mine has been in operation since 2003 and
plays a crucial socio-economic role with South
Africa being the world’s largest producer of platinum. It has 5,000 employees in total and contributes significant wealth to the country’s gross
domestic product (GDP).
The mine is made up of two shafts, North and
South; and is a 240,000t per month platinum
production facility. Employing a hybrid mining
technique where mechanised methods are used
Rudi Coetzee, Engineering Foreman, Modikwa
“The MTU Series 900s are relatively new engines, especially in the South African market. They have been
operating in Sandvik vehicles on Modikwa for two and
a half years. In this time, they have outperformed others in their class.”
South Africa
for the main developments and the narrow, 60cm
reef is conventionally stoped using a down-dip
method. While excavation of the ore is done by
conventional means, the mine employs trackless
mining vehicles, which entails the use of tyre-driven or mobile machinery underground as opposed to using tracks as was prevalent in the past.
This offers greater flexibility of the fleet as it is
not constrained to one area or one level of the
mine and machinery can move to and from production points much faster.
Machines with MTU Series 900 engines
With its 6m long boom reaching to the face, drill
rigs pierce the solid earth, punching holes approximately 5cm wide; just enough to house and
make way for the explosives. If the drill rig goes
down, production slows. And in an operation that
One drill rig is driven by a MTU type 4R 904 engine with rated power
of 129 kW at 2,200 rpm.
loses on average R10 million for each day that
production stops, reliability and peak performance are non-negotiables. It is one of the only
machines at Modikwa that stays underground,
even as blasting takes place.
the engine delivers: rated power of 129kW at
2,200rpm. Rudi Coetzee, engineering foreman at
Modikwa and responsible for all machinery on
the North shaft, confirms this, “The MTU Series
900s are relatively new engines, especially in the
South African market. They have been operating
The three drill rigs on North and South shaft stay in Sandvik vehicles at Modikwa for two and aunderground for a full week, being re-fuelled
half years. In this time, they have outperformed
underground from containers delivered to it,
others in their class.” Sandvik South Africa has a
when required. One drill rig is driven by a MTU
performance service contract with Anglo Platitype 4R 904 engine. Looking at the distances
num to service the machinery. This includes
this machine has to drive underground — a one- dump trucks and load haul dumpers (LHD) as
way distance from decline to the face of up to
well as drill rigs and roof bolters deployed under4.5km — the most impressive feature is the power ground, in the development of the mine.
Once the drill rig has finished its work, the face
is charged up with explosives, and then blasted.
After blasting, the LHD loads ore which is put
into a dump truck and moved from the face to
the conveyer belt. The conveyer belt takes the
ore out to the plant. One of the dump truck applications is powered by a MTU type 6R 926 C72
engine with rated power of 240kW at 2,200rpm.
Being one of the smaller dump trucks on the
mine, it more than makes up for its size in workload. For this reason it is crucial that it remains
working; for maximum periods, at maximum
output. This is certainly evident at Modikwa, as
Coetzee explains, “The MTU type 926 engine is
performing at an excellent rate of approximately
210 to 240 hours of running time per month. The
standard time is usually between 110 and 180
hours, which is also good. Certainly a great endorsement at an operation that, on average, generates up to R1 million an hour on these units.
Conditions above ground and underground
for the engines
With high temperatures and a healthy annual
rainfall, the lush, subtropical conditions on the
surface mask the harshness of the underground
environment. In this part of Limpopo the temperature in summer is up to 42°C while in winter it
plummets to an average of -2°C. During the rainy
season, the area is known to receive in excess of
200mm of rain in a 24 hour period. Furthermore,
21 mines in operation in the area and another 16
planned for development, attests to the fact that
it is one of the highest concentrations of lightning strikes in South Africa. Everything that happens underground is intense. Heavy machines
manoeuvre through tight spaces. It is abrasive
and combative. The sound is deafening, temperatures reach in to the mid 40s°C — sustained
by the heat that the hard-working engines produce. Dust plays its part in challenging engine
performance and in the newly developed areas
it is flooding that is the major issue. Water manifests from underground due to seepage and a
high water table.
Additionally, the drilling process produces water.
It is not uncommon for an MTU service technician to be working knee deep in water, while
servicing a vehicle underground. “It is important
that the MTU Series 900 engines operate no
matter what conditions are experienced underground,” explains Coetzee. “The biggest challenge is the vast temperature range and the
potential problems related to this.” Because the
mine forms a closed loop system, cold ventilated
air has to be physically pushed through the mine
from the surface. Furthermore, burning as little
fuel as possible and the after effect of releasing
carbon monoxide, which needs to be pushed out
of the mine by a fan is fundamental. “These challenges are considered when selecting machinery
and equipment to work underground,” says the
engineering foreman.
Fuel consumption — low and efficient
Automated features on the MTU Series 900 en-
The drill rig, with its long arms, punches holes into development
ends where explosives are inserted and the face is blasted, opening
up the ends for further production at Modikwa.
Thomas Phiri, Sandvik Contracts Manager
gines are what excite Coetzee the most, that is,
the ability to have the engines think for themselves underground. Asked what features they
thought most significant in fuel efficiency, Coetzee quickly states, “As the engines have the
capability of decelerating themselves, this automatically results in improved fuel consumption.
Additionally, if the correct amount of oil is not
put into the engine, it just will not start.” Coetzee sees the great benefit in the automated idling component. The engine can be set for a ten
minute period of idling, for example, while waiting for the ore to generate. It depowers itself,
cutting down the engine, using less diesel and
pushing out less exhaust gas. “The less gas and
heat they emit, the cooler the mine underground.
Moreover, the low consumption rate keeps the
cost per ton of material moved low at Modikwa,
and that is crucial,” says Coetzee.
their entire service lives as they are when new.
This enables the system to compare the readings
obtained from the sensors with the target settings for optimum engine performance.
criteria for selecting an engine or a machine
group is after sales service. We must know from
the company that we are dealing with that they
are willing and able to help us 24/7, because we
run all the time. We don’t stop for Christmas or
This ensures that the engine is stable in terms of New Year’s, it’s a 365 day production line. MTU
fuel consumption, emissions and performance
was one of the few companies that could stand
over the entire lifespan, since the engine manage- behind us and make people available for those
ment system ensures that compensation is made times.”
for any changes resulting from wear and tear and
environmental conditions. Thomas Phiri, Sandvik Currently MTU is permanently on-site, with one
Contracts Manager, sees the benefits from a
representative per shaft, every day, Monday to
service point of view, “The ECM assists with fore- Friday. This involves checking and maintaining
casting. We can predict when the engine is going the machines, downloading information and
to need maintenance, as well as indicating the
providing parts. Moreover, the MTU representaservices required, components to change, as well tives are also on 24 hour stand-by. Phiri can
as new components needed in order to extend
therefore focus more time on other parts of his
the life of the engine. From the history of operati- job, asserting that, “Because the MTU service
on on the machine my team sit down and plan
technician is on-site to give us advice on the
what work needs to be done on the engine.” The- engine before major problems arise, it gives us
MTU automation system
re is also a powerful protective element that enan advantage. Having an arrangement with MTU
The engine control module (ECM) on both MTU
sures the engine is not mistreated. The protection assists Sandvik in minimising engine downtime
type 904 and 926 engines enables the precise
is provided in the form of sensors which indicate and the cost of the machine. Furthermore, MTU
interaction between key engine systems. With
coolant temperature and engine temperature. If
transfers skills and knowledge to Sandvik serthe ability to extract and analyse crucial informa- the temperature increases in an irregular manner, vice technicians and mine vehicle operators and
tion, gathered from the engine over an extended the ECM will raise an alarm, and if ignored the
artisans. From Sandvik’s perspective, this helps
period, engine lifecycle, engine performance,
engine will de-rate to limp mode (reduced power), in keeping our client happy.”
mine operating efficiency and a host of other
saving it from getting destroyed or harmed.
areas are dramatically improved. The system
When an engine goes down while underground at
prevents further deterioration that could result in After sales service
Modikwa, MTU is called and the problem must
major costs and quicker loss of the engine. It
MTU works on a service exchange basis, estima- be rectified within a specified period. “Our target
also improves planning, making sure that it does ting a down time of between eight and 24 hours is always two hours in which that machine must
not impact the mining or production staff while
for replacing an engine. If not planned correctly, be up and running,” says Phiri. Previously MTU
making it easy to determine the service needed, the machine can stand for up to two weeks wai- technicians were called out from Johannesburg,
resulting in a decrease of downtime for the ope- ting for parts, at great costs. This is one of the
360km away. A localised MTU service point was
ration at Modikwa. Long-term stability of the
reasons Coetzee is passionate about service and set up in the little town of Burgersfort, 20km
engine functions to ensure that MTU engines
the impact good after sales service has on mafrom the mine, improving their service and
remain as economical, clean and powerful over
king his job easier. “The single most important
strengthening their commitment to Sandvik.
MTU Friedrichshafen GmbH
A Rolls-Royce Power Systems Company
www.mtu-online.com
MTU is a brand of Rolls-Royce Power Systems AG. MTU high-speed
engines and propulsion systems provide power for marine, rail,
power generation, oil and gas, agriculture, mining, construction and
industrial, and defense applications. The portfolio is comprised of
diesel engines with up to 10,000 kilowatts (kW) power output, gas
engines up to 2,150 kW and gas turbines up to 35,320 kW. MTU also
offers customized electronic monitoring and control systems for its
engines and propulsion systems.
3082601
July 2012
Photo credits: Pages 1, 2 (bottom) and 3, Francesca van Rooyen. Page 2 (top), MTU.
“Because the MTU service technician is on-site to
give us advice on the engine before major problems
arise, it gives us an advantage. Having an arrangement with MTU assists Sandvik in minimising engine
downtime and the cost of the machine.”