MINING ENGINES
Cat’s recently launched R2900 underground
loader is equipped with a six-cylinder, 305 kW-
rated C15 engine, which uses the Cat Clean
Emissions Module to limit both PM and NOx to
near zero
These three companies went around their
product development in similar fashions to
deliver the emission-compliant engines.
As Cummins’ Lintereur said: “Stage V in 2019
is the first time our mining products have been
impacted by emissions regulations in Europe.
Our proven solution for EPA Tier 4 Final using
selective catalyst reduction (SCR) allows us to
meet Stage V and provide installation
consistency for original equipment
manufacturers.”
Cummins selected SCR for Tier 4 Final and
Stage V because it delivers the best balance of
installation, efficiency and total cost of
ownership (TCO), the company said. The fully
integrated after-treatment unit replaces the
exhaust muffler, minimising design
modifications, while reducing nitrous oxide (NOx)
levels to Stage V requirements. The SCR system
also features an integrated decomposition
chamber and Cummins’ airless dosing system,
designed to last the life of the engine.
SCR reduces engine backpressure helping
increase fuel economy and optimise temperature
management, according to Cummins, while
minimising Adblue/diesel exhaust fluid (DEF)
consumption.
Sean Lynas, General Manager of Off-Highway
OEM Accounts for Cummins, told IM the use of
SCR on the company’s Tier 4 Final engines in
high horsepower applications for the US market
had worked well, so it made sense to pursue a
similar strategy in Europe for Stage V.
“Our ambitions for Tier 4 were essentially to
be TCO and fluid neutral between US Tier 2 and
Tier 4 Final, so the use of SCR wouldn’t be a
penalty in any way. I think we have been pretty
successful in that,” he said.
Lintereur concluded: “Having a common
installation for Tier 4 Final/Stage V and
34 International Mining | JULY 2019
unregulated regions, with the exhaust system
being the key difference, helps our OEMs build
product to use in any territory. They can develop
common chassis designs with one engine solution
from us to meet the needs of all regions.”
Cat, meanwhile, has leveraged a combined
Tier 4 Final/Stage V solution across all its large
mining truck engines to comply with the
respective emission regulations. This has
involved accumulating over 100,000 field hours,
which included completing a planned engine
rebuild.
Comparing its US EPA Tier 4 Final engines with
its Tier 2 equivalent, Jeff Castleman, Business
Development Manager, Large Mining Trucks, told
attendees of a November Caterpillar event in
Tucson, Arizona, that PM and NOx gas emissions
had been reduced by 93% and 62%, respectively.
This is thanks to the use of an SCR system
using DEF to remove NOx.
Castelman said the company went down this
route on engines for its large mining trucks as it
was a proven emission system with over 20
million hours of field operation, it offered a lower
overall fluid and fuel consumption – lowering
TCO – had a long life to overhaul (as well as
multiple lives), involved common designs and
processes, and facilitated ease of service and
operation.
He went on to show how TCO had fallen on
these new engines in a trial comparing a Tier 2-
equipped Cat 793F haul truck with a Tier 4 Final-
equipped Cat 793F haul truck.
Overall, the TCO came down 2.2% in this
study, which factored in DEF use, repair and
maintenance and diesel use. At the same time as
this, the 793F with Tier 4 Final engine maintained
its payload performance.
The results were similar across the large
mining truck range, Castelman added, with those
Tier 4 Final field hours coming from 785G trucks
working in cold weather climates on coal
operations, to 794 ACs running around deep pit
copper mines and 797s operating in Canada’s oil
sands.
When it comes to machines more likely to end
up in underground mines, Cat uses a similar
approach.
In Cat’s more compact range of engines (C3.6-
C18 (560 kW and below)), it uses a mix of
exhaust gas recirculation and SCR, which also
requires diesel oxidation catalyst (DOC)
aftertreatment and a DEF system, to meet Tier 4
Final/Stage V emission criteria. The exhaust
aftertreatment devices are packaged in a Cat
Clean Emissions Module (CEM).
For example, its recently launched R2900
underground loader, which is equipped with a
six-cylinder, 305 kW-rated C15 engine, uses SCR,
DOC and a DEF system to limit both PM and NOx
to near zero, allowing the machine to meet EU
Stage V and Canada’s CANMET standards.
MTU, meanwhile, based its Stage V engines on
Daimler commercial vehicle engines, with the new
limits achieved by internal engine enhancements
and adding an SCR system and DPF.
Rolls-Royce Power Systems offers a one-box
solution featuring SCR, DOC and DPF to integrate
all components into the limited installation space
of the machines. “This exhaust gas
aftertreatment system is both compact and
robust,” the company said, adding that the box
meets the requirements of vehicle manufacturers
and operators by being simple to install, operate
and maintain.
Fuelling the emission compliance
Fuel is a major cost for truck haulage,
representing 30-40% of equipment operating
costs, according to vertically integrated fuel
filtration company Donaldson. As a result, fuel
savings of even just a few percentage points can
save thousands of dollars per year in even the
smallest fleets. At the other end of the scale, if
the fleet for a large mining operation uses 1%
less fuel, it can mean millions of dollars in
annual savings.
Tier 4 and Stage V emissions regulations have
compelled engine manufacturers to improve the
efficiency of their engines, with the challenge
being achieving this while also needing to burn
more fuel to achieve production levels.
Jason DeGuelle, Product Manager – Engine
Filtration, Donaldson, said: “Changes to the way
engines are built have, in turn, brought changes
in the standards for acceptable diesel fuel
cleanliness.
“High-pressure common rail engines have
been designed to improve fuel economy as well
as reduce emissions,” he said. “As a result,
injectors run at much higher pressures, requiring
tighter tolerances and clearances – which is why
they need much cleaner fuel to operate at an
optimal level.”
On major mining sites, unplanned downtime
for any reason is a significant problem. “Effective