appropriate gear for the movement.
Focus can instead be directed on
carefully manoeuvring the truck
across the difficult terrain in a safe
manner. This not only reduces the
stress that a driver endures when
operating a fully loaded truck in
desert conditions, but also lowers
the need for any advanced training,
as the automatic gearboxes are easy
to operate. This ease-of-use also has
the advantages of helping eliminate
bad driving habits, as the correct
gear is always selected, cutting out
incidences of over-revving the
engine and grinding gears, thus
reducing both engine and
transmission wear.
By using a carefully configured
torque converter, the automatic
transmission system can deliver
maximum torque both in first gear
and at a very low RPM. This is vital
when the Xi Bei Lang trucks need to
carry out their cliff-side
manoeuvres, as the delivery of
continuous torque through the
powertrain helps prevent any wheel
spin and jerking when the trucks
take-off after dumping their cargo.
This is a problem that was inherent
in the manual transmissions found
in the previous fleet of dumper
drucks. These trucks would slide
backwards when attempting to
climb the mine’s steep inclines of
over 200 m, making difficult
drop-off manoeuvres that much
more demanding.
As the Allison Transmission
system removes such problems, the
downtime required for tired drivers
and trucks with overworked
powertrains is reduced,
improving productivity.
The transition of
transmission
While the aforementioned
manoeuvre highlights the benefits of
an Allison Transmission system
when it comes to truck drivability
and operation, the need for little, no
regular or unscheduled maintenance
is key in propelling productivity
performance of powertrains.
Before purchasing the Xi Bei Lang
mining dump trucks, Xinjing Coal
imported trucks equipped with
manual transmissions to carry out
transport duties on the site. As the
mine’s unforgiving terrain requires
truck drivers to make constant gear
changes, it led to countless
breakdowns that required repair
parts. These could take a month or
longer to ship from OEMs overseas.
At one time, there were as many as
50 manual vehicles awaiting repair;
these trucks sat idle at a cost of
3000 – 4000 yuan/day per driver.
Such downtime needed to be
avoided if the Xinjing mine was to
operate efficiently.
Since automatic transmission
systems select the ideal gear for the
road conditions, powertrain wear
(and associated maintenance) is
avoided. Where time and
productivity has such a significant
effect on a mining operation’s bottom
line profits, reducing the need for
maintenance – scheduled or
otherwise – is a margin enhancing
prospect that mining fleet operators
cannot ignore.
Conclusion
When considering the proven effect
it can have on a mining operation’s
productivity, it seems clear that the
careful combination of reliable,
high-performance off-highway
powertrain components is a vital
part of fleet specification. This is true
both before and during a mining
operation. In a crowded and
competitive industry, the powertrain
could be the difference between
failure and significant success for
both mining companies and
vehicle OEMs.
36
|
World Coal
|
September 2014
“Allison transmissions have high reliability and provide excellent maneuverability,” dump truck driver, Baoan, concluded. There is
nothing to worry about, as his truck dumps its 30 t load over a nearly 90˚cliff in the Gobi Desert.
