Diesel filter testing shows promise
Underground field trial at Copper Cliff Mine shows 95 to 99 per cent elimination of diesel particulate and noxious gases
A filter undergoing field trials on a Caterpillar 1700 LHD at Vale’s Copper Cliff mine is dramatically reducing harmful diesel particulate emissions and noxious gases.
“The numbers are really, really good,” said Peter Golde, managing director of the Sudbury-based Canadian Mining Industry Research Organization (CAMIRO). “We’re getting anywhere from 95 to 99 per cent of all the (diesel particulate and gases) removed.”
The Diesel Emissions Reduction Research Project is funded by a consortium of mining companies – Vale, Glencore’s Sudbury Integrated Nickel Operations and KGHM International – and managed by CAMIRO.
The principal investigator is Dr. Joe Stachulak of MIRARCO-Mining Innovation, formerly Vale’s manager of strategic ventilation.
The numbers obtained from regular sampling of the emissions are borne out by personal experience, said Golde, who joined CAMIRO following a 26-year career with Inco and Vale, most recently as manager of the company’s Sudburybased R&D team.
“Normally, when you’re driving up a ramp, you can smell the diesel and you feel the air getting heavy with fumes,” he said. “We were driving up behind the test machine and you don’t have any of that smell, that heavy, diesel-laden air that you’d normally be breathing in following a machine up a ramp. If you take your finger and swipe around the exhaust, there’s no soot. It’s perfectly clean, so there’s a very dramatic improvement in the cleanliness of the exhaust with this system in place.”
The Johnson-Matthey filter isn’t new, but it has never been used on this size engine or in an underground mining application.
“The filter is a fairly large device,” said Golde. “It sits just alongside the engine compartment at the rear of the LHD.”
It consists of two large canisters, one of which could only be accommodated on the test machine by removing one of the LHD’s twin fuel tanks.
“There may be a better way of installing it in a full production scenario, but it does require a bit of space,” said Golde.
Minimal operator maintenance is one of the main requirements for a diesel particulate filter in an underground production environment.
The Johnson Matthey filter does have to be cleaned out after “so many thousand hours,” said Golde, but it’s basically maintenance free otherwise, requiring no daily tweaking and nothing that would impede productivity.
“The particulate is burned off, but you need to build up the exhaust temperature to a certain level, and for that you have to run the machine fairly hard for a sustained period of time. For a haul truck, you need to be going up a ramp under load to achieve that exhaust temperature.
The worst thing you can do is let the machine sit there and idle for extended periods of time.”
Surface testing of the filter began in 2012 at Vale’s Totten Mine. The plan was to continue the field trial underground at Stobie Mine, “but that didn’t work out and we spent a year looking for a new home,” said Golde.
In the end, Copper Cliff Mine volunteered to take it on, allowing the underground field trial to begin in April.
The CAT 1700 has chalked up approximately 250 hours of run time in an operational stoping area, but is only being used on certain shifts by dedicated operators and under controlled circumstances “because we didn’t want someone driving it into a sump and shorting out all the electronics, which sometimes happens in a production setting,” said Golde.
The ultimate objective is to complete 1,000 hours of testing, which is expected to take another six months. At that point, Golde and Stachulak hope to be in a position to give the filter a thumbs up.
New Tier 4 diesel engines, which are slowly being introduced by original equipment manufacturers, have stringent emission standards.
However, it’s not clear how suited they are for underground applications and may require some testing and further modifications.
“There are a few Tier 4s around, but the industry hasn’t had much exposure to them, nor have we done any real assessment of the impact they will have, so it’s something we need to follow up on,” said Golde.
Ultimately, original equipment manufacturers will offer up a solution – either the Johnson-Matthey filter CAMIRO is testing or some alternative. However, in the meantime, there are more than 850 diesel-powered vehicles in operation in Sudbury’s mining industry that could be retrofitted to improve the underground environment.
The objective of the Diesel Emissions Reduction Research Project “is to make sure that any new (filter) technologies are in the best interest of the mining industry, that they will work reliably from a maintenance standpoint and that they will consistently produce the results we’re looking for,” said Golde.