DEEP project on evaluation of diesel particulate filters at Inco’s Stobie Mine

J.S. Stachulak & B.R. Conard

Inco Limited

A.D. Bugarski & G.H. Schnakenberg, Jr.

National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory

ABSTRACT: The objective of the Diesel Emissions Evaluation Program (DEEP)-sponsored project at Inco’s

Stobie mine was to conduct a long term field evaluation of diesel particulate filter (DPF) systems available to

the underground mining industry. Some of the major issues studied were criteria for selecting the filter media,

means of DPF regeneration, efficiency of DPF systems and the occurrence of unwanted secondary emissions,

and reliability and durability of DPF systems. Nine state-of-the-art diesel particulate matter (DPM) filtration

systems have been retrofitted to heavy-duty and light-duty vehicles and have been subjected to extensive longterm in-mine evaluation. Periodic efficiency tests were conducted at various stages of the study (2001, 2002 and

2004) to establish in-use efficiencies and durability of the tested DPF systems. The results were used to assess

the effects of the filter systems on the concentrations of particulate matter, nitric oxide, nitrogen dioxide and

carbon monoxide in the vehicle exhaust. The variety of filtration systems and regeneration concepts used in this

study offered the opportunity to investigate their advantages and disadvantages. This paper also offers a review

of selected experiences with the installation and operation of the DPF systems on underground mining vehicles

at the Inco Stobie Mine.

1 INTRODUCTION

Since their introduction into underground mining

operations in the mid-1960s, diesel powered equipment has become increasingly employed and recognized as the workhorse in mining. Diesel engines

proved to be relatively durable, easy to maintain and

generally to have relatively low operating costs. Inco

Limited employs over 800 diesel-powered units at

its Ontario mining operations in the Sudbury basin.

Although the use of alternative sources of power (e.g.,

electricity, fuel cells) is being explored, Inco and most

other Canadian deep-rock mining companies realize

that diesel engines will continue to be a very important source of power for growing fleet of heavy- and

light-duty vehicles for many years to come. In view of

this, it is imperative to lessen adverse effects of diesel

emissions on quality of the air in underground mines.

A Canadian industry/labor/government consortium, Diesel Emissions Evaluation Program (DEEP),

was formed in 1999 to address issues related to exposure of underground miners to diesel particulate matter

(DPM). One of the major objectives of this program

was to identify strategies and controls that will attain a

tenfold reduction in miners’ exposure to DPM. DEEP

sponsored two projects, one hosted by Noranda’s

Brunswick mine (McGinn 2004) and the other hosted

by Inco’s Stobie mine (Stachulak et al. 2005a) that

tested existing diesel particulate filter (DPF) technologies in operating mines. The long-term study,

conducted under DEEP auspices at Inco’s Stobie mine

from April 2000 to December 2004, assessed the suitability and effectiveness of selected DPF systems for

control DPM emissions from heavy- and light-duty

underground diesel mining equipment.

Diesel exhaust is complex mixture of gases, liquids,

and solids. The gaseous phase includes carbon monoxide (CO), carbon dioxide (CO2), nitric oxide (NO) and

nitrogen dioxide (NO2) (in combination termed NOx),

sulfur dioxide (SO2) and sulfur trioxide (SO3) and a

number of low molecular weight hydrocarbons (HC).

The liquid or vapor phase includes condensed hydrocarbons of varying molecular structures and sulfuric

acid aerosols, which are formed by the combination of sulfur trioxide with water. The solid phase,

commonly known diesel particulate matter, is predominantly made of elemental carbon (that arises from

partially burned fuel), ash and sulfate aerosols (see

Figure 1). The metals contained in these compounds

originate from lubricating oil and impurities in the

fuel. The majority of these diesel-produced particles

are submicron in size and therefore respirable. Due to

143
Figure 1. Schematic of diesel exhaust particulate.

Figure 2. Typical constitution of diesel exhaust (after

Burtscher, 2005).

the small particle sizes, the elemental carbon particles

provide a large surface area suitable for adsorption

and absorption of volatile and semi-volatile hydrocarbons. These hydrocarbons constitute the soluble

organic fraction of diesel particulate matter. Typical

chemical composition of diesel particulate matter is

shown in a pie chart in Figure 2 and a typical particle

size distribution, summed over the operating modes of

a diesel engine, is shown in Figure 3.

Physical properties and chemical composition of a

diesel engine’s exhaust were found to vary as a function

of a number of parameters including engine design,

age, operating conditions, maintenance, type of fuel,

etc. It is important to recognize that there are certain

limitations and trade-offs in controlling these parameters in an effort to minimize potentially harmful emissions from diesel engines. It is apparent that substantial

reduction in emissions of a number of components of

diesel exhaust are achievable only by various combinations of exhaust after-treatment technologies such

as diesel oxidation converters (DOCs), diesel particulate filter (DPF) systems, selective catalyst reduction

(SCR) systems, etc.

DOCs are widely deployed by the underground mining industry for control of CO and HC emissions from

diesel engines (Stachulak 2003). Those devices were

found to be relatively easy to operate and maintain. On

the contrary, controlling DPM emissions was found to

be substantially more challenging (Schnakenberg and

Bugarski 2002). Improvements in fuel quality (Watts

et al. 1998) and maintenance, as well as improvements in engine design, operation and ventilation, were

shown to be insufficient to accomplish a desired 90%

reduction in DPM. It became apparent that removal

Figure 3. Typical particle size distribution of DPM (after

Kittelson, 1998).

of DPM from the exhaust stream using diesel particulate filter systems was likely to be an integral part

of the strategy to achieve dramatic reductions in DPM

emissions (Conard and Stachulak 2000).

The first ceramic monolith DPF for use in underground applications was developed by Corning Glass

in collaboration with Natural Resources Canada

(CANMET) scientists. In the early 1980s prototype

systems were laboratory-tested and then taken underground for field trials (McKinnon 1989). Inco was

involved in testing a prototype at Little Stobie Mine

(Stachulak and Conard 2001) and in implementing

what was then considered to be a successful technology via the National Research Council’s Program

for Industry/Laboratory Projects (PILP) run under the

auspices of the Collaborative Diesel Research Advisory Panel. However, initial success was afterward

impeded by long-term implementation issues. Frequent problems with filter regeneration – burning-off

of the collected DPM – often resulted in unacceptable engine backpressures. As a result, many of these

systems were eventually rejected by vehicle operators.

Mine management, as well as workers, became skeptical of the technology. It is now recognized that the

performance of a filter is intimately associated with

successful periodic regeneration of the filter. The early

implementation of filters on underground equipment

relied on this removal being done by the heat in the

engine exhaust itself and, as now realized, sufficient

temperatures were not achieved for many DPF systems because of a combination of lower than expected

exhaust temperatures and/or a lack of sufficient time

at high exhaust temperature to complete regeneration.

VERT, a European project, evaluated the best technology to curtail DPM emissions from engines used

in construction and tunneling operations (Mayer et al.

1998). Both laboratory testing and field evaluations

of various control technologies were conducted under

auspices of this project (Mayer et al. 1999, 2002). Discussions between DEEP and Andreas Mayer, VERT’s

technical director, assisted greatly in developing the

Stobie project’s scope of work. VERT’s list of tested

and approved DPFs for retrofitting diesel engines

(SAEFL 2003) was extensively used during the DPF

144
selection process for the Stobie project. The knowledge gained by VERT in successfully matching engine

and DPF system characteristics was particularly valuable to the DEEP researchers.

As a result of the high demand for after-treatment

systems to control diesel particulate emissions from

on-road and off-road vehicles, DPF technology rapidly

advanced in recent years. Some of these technologies

are in wide use in on-road applications, but have not yet

been tested and proven for underground mining applications. Therefore, in light of the increased concern

on the effects of DPM on human health and recent

developments in control technology, DEEP decided

to sponsor long-term evaluation of six DPF systems

retrofitted on production and support vehicles in the

Inco Stobie mine fleet. The specific objectives of the

project were to:

1 develop methods for selecting DPF systems for

underground mining vehicles;

2 determine the ability of tested DPF systems

to reduce DPM emissions without significantly

increasing secondary emissions of other noxious

substances;

3 evaluate the long-term durability and reliability of

the tested DPF systems;

4 establish operational and maintenance costs for

such systems;

5 develop Canadian expertise on the DPF technology

and DPM measurement methods.

The project was initiated in early 1998 with the

generation of a proposal for conducting the study.

The proposal was peer reviewed by DEEP’s Technical

Committee and outside reviewers, and the project was

officially approved in mid-1999. Originally planned

to be conducted over roughly 2.5 years, the testing

was extended to December 2004 primarily to enable

reasonable operating hours to be accumulated by the

systems so that an assessment of long-term reliability

and durability was possible.

2 METHODOLOGY

2.1 Test vehicles

Five heavy-duty load/haul/dump (LHD) vehicles were

selected as representing the primary heavy-duty

workhorse in underground mining. One of these units

had a dual exhaust Deutz engine and the other four had

Detroit Diesel Series 60 engines. The engines spanned

a range of age and service use.

Two Kubota tractors powered by Kubota F2803B

engines were selected as being representative of light

duty vehicles, which are increasingly being used in

transporting underground personnel. DPF service on

light-duty underground mining vehicles had not been

studied anywhere at the time the Stobie Project was

Figure 4. Exhaust temperature histogram for production

LHD vehicle.

started. Their inclusion in the Stobie testing was considered important, because the contribution of lightduty vehicles to concentrations of diesel pollutants in

underground mines is increasing (Rubeli 2003).

Temperature and pressure sensors were installed

upstream of the muffler on the each candidate vehicle and data were collected at 1 Hz frequency using

on-board data acquisition systems. The temperature

and engine backpressure data were collected for six

months prior to the final selection the DPF systems for

testing. The temperature traces were used to generate

exhaust temperature histograms. Temperature traces

and histograms were needed in DPF system selection

to assess whether the engine-produced exhaust temperatures and heat were sufficient to sustain partial or

even complete passive regeneration of filters. These

data were found to be absolutely essential for selection,

installation and optimization of DPF systems (Mayer

2000).

As illustrated on the example histogram shown in

Figure 4, the engines in heavy-duty LHD vehicles did

not routinely achieve high enough exhaust temperatures (∼600◦C) for long enough periods to support

complete regeneration of uncatalyzed DPF systems.

This meant that DPF systems retrofitted to LHDs

needed to be catalyzed to support passive regeneration

at relatively lower exhaust temperatures. The alternative to those systems were active systems regenerated

with help of external sources of energy. Similarly,

data on light-duty vehicles clearly showed the need

for active regeneration. The data on all vehicles indicated that engine backpressure would be an important

diagnostic tool for monitoring the status of the DPF

systems.

2.2 Selection of DPF systems

The temperature traces and other information relevant

to the selection and optimization of the DPF systems

were supplied to potential DPF system suppliers. The

145
DPF systems were required to meet criteria developed byVERT (SAEFL 2003).The resulting proposals

from suppliers were thoroughly reviewed by DEEP

Technical Committee, Inco’s Stobie team and external

reviewers.

Two of the LHD vehicles powered by Detroit Diesel

Series 60 engines were retrofitted with completely

passive systems: an Oberland-Mangold DPF system

with a knitted glass fiber filter and a dosing system

for fuel-borne catalyst on one, and an Engelhard DPX2

DPF system with a catalyzed cordierite monolith on

the other. One of the remaining LHDs, also powered by Detroit Diesel Series 60, was retrofitted with

a completely active system from ECS/Unikat with a

SiC monolith filter and an on-board electrical heater

for off-duty regeneration. A Johnson Matthey passive/active system DPF 201 with a SiC (or cordierite)

monolith was retrofitted to the dual exhaust Deutz

engine. This system was partially regenerated passively with help of a fuel-borne catalyst. The complete

regeneration of these filters was secured with on-board

electrical heaters. Two light-duty Kubota tractors were

retrofitted with active DPF systems: one with an ECS/

3M with a ceramic fiber filter and an on-board electrical heater; the other with a DCL system with a

removable SiC monolith that was regenerated using

an off-board electrical heater.

At a later stage of the project the Oberland-Mangold

DPF system was replaced, due to technical problems,

with an ECS/Unikat DPF system with a SiC monolith filter and an on-board electrical heater. Similarly, the ECS/3M DPF system was replaced with an

ECS/Unikat with a SiC monolith filter and an on-board

electrical heater. In the third year of the project one

additional LHD powered by a Detroit Diesel Series 60

engine was fitted with a prototype active DPF system

from Arvin Meritor. This system was designed around

a cordierite monolith filter and an on-board diesel

fuel burner for regeneration during normal vehicle

operation.

More detailed descriptions of the evaluated DPF

systems, test vehicles, and DPF installations are available in Stachulak et al. 2005a.

2.3 Measurement of emissions and other relevant

parameters

Each vehicle was brought in for general maintenance at

least every 250 hours of operation. The effects of DPF

systems on the emissions were measured at torque converter stall steady-state engine operating conditions.

Emissions of NO, NO2, CO, and CO2 were examined

using an ECOM AC portable gas analyzer. That analyzer was also used to determine the Bacharach smoke

number upstream and downstream of each system.

More extensive emission tests were conducted in

July 2001, May 2002, and June 2004 under three

reproducible steady-state engine operating conditions:

(1) torque converter stall, (2) high idle, and (3) low idle.

The concentrations of NO, NO2, CO, and O2 were measured upstream and downstream of the systems using

ECOM KL and AC portable gas analyzers. Particulate

concentrations were measured upstream and downstream of the systems using a photoelectric aerosol

sensor (PAS 2000 from EcoChem Analytics) and an

opacity meter (DiSmoke from AVL). Particle size distributions and concentrations were measured using a

Scanning Mobility Particle Sizer (Model 3926 from

TSI Inc.).

Industrial hygiene (workplace) measurements were

conducted for “with filter” and “without filter” conditions while selected test vehicles were performing

normal production duties. Ten particulate samples

were collected for each test: three samples for RCD

analyses and three samples for elemental carbon (EC)

analyses were collected on the test vehicle just behind

the driver; two samples for EC analyses were collected at the fresh air supply; and two EC samples

were collected at the exhaust air outtake. Air flow

measurements were performed during each test period.

All test vehicles were equipped with temperature

(TS-200 EGTS from Heraeus) and pressure (Series

BT8000 from SensorTechnics) sensors and data acquisition systems (Model FCD-001 from Paul Nöthiger

Electronics). The exhaust temperature upstream and

downstream of the DPF systems and engine back pressure data were collected throughout study at 1 Hz

frequency.

3 RESULTS AND DISCUSSION

3.1 Selection of DPF systems

The process of critically evaluating DPF system design

with a vehicle’s duty cycle was found to be essential for selecting the optimum DPF system. Gathering

adequate information specific to each individual application was found particularly important for making

educated decisions on selection and optimization of

each DPF system with regard to both its regeneration method and the filter’s proper sizing. Actual

exhaust temperature profiles and good estimates of

in-use DPM emissions are critical inputs for selecting

DPF systems.

The experience gathered during this project was

used to complement VERT filter selection criteria

(SAEFL 2003) to cover specifics of underground

mining applications:

1 The system should have efficiency of 95% in

removal of both particulate number and elemental

carbon mass (NIOSH 5040);

2 The system should provide adequate regeneration

over mining cycle;

146
3 Backpressure must meet vehicle/engine warranty:

New DPF 50 mbar

Regenerated DPF 60 mbar

Before cleaning <150 mbar.

4 The system should be supplied with adequate

temperature and engine backpressure monitoring

transducers, data acquisition system, and appropriate displays;

5 Secondary emissions (catalyzed traps are the concern):

6 preferably no increase of NO2, but in any event

the system should not increase ambient NO2 concentrations above 0.8 ppm at a ventilation rate of

100 ft3/hp;

7 Copper is not permitted in any catalyst formulation

(fuel or filter) due to the potential for increases in

formation of dioxins;

8 The system should be rugged enough for underground mining applications;

9 The system should be CSA & CEC approved and

equipped with fire suppression systems;

10 Useful life of the system should be 3 years or 9000

hours.

3.2 DPF sizing

Elevated engine backpressures, substantially exceeding the manufacturer’s recommended maximum values, were recorded during operation of several tested

systems. For example, the backpressure on the engine

equipped with Engelhard DPX2 DPF system frequently exceeded its manufacturer-recommended values, periodically exceeding 300 mbar for extended

periods. The turbocharger on that engine eventually

failed and caused an oil fire. At this time is not

clear what role the DPF system and elevated engine

backpressure may have played in the turbo failure. In

general, the effects of prolonged elevated backpressure

on performance and durability of a diesel engine are

not very well established and more research is needed

to address this issue. It is clear, however, that failure

to regularly regenerate an filter and maintain engine

backpressure within recommended limits eventually

resulted in failure of the filter element.

DPF sizing was found to be particularly important for active systems in which an inadequately sized

filter could potentially impact vehicle usability and

productivity. It is important to consider the limitations

imposed by restricted space on the vehicle, together

with safety and maintenance issues.

3.3 Effects of DPF systems on particulate and

gaseous emissions

The emissions tests showed that the evaluated DPF systems, if properly installed and maintained, can provide

reductions in DPM emissions targeted by DEEP. The

majority of tested DPF systems provided reductions in

tailpipe DPM concentrations measured by PAS 2000

in excess of 90%. Similarly, elemental carbon analysis showed twenty-fold reductions for several tested

systems. Size distribution and concentration measurements in the exhaust systems showed reductions in

total number of diesel aerosols in excess of 95%. The

effects of DPF systems on gaseous emissions were also

closely investigated. The uncatalyzed DPF systems

were found to have minor effect on tailpipe concentrations of CO, NO, and NO2. Very low concentrations

of CO downstream of the filter and a two-fold increase

in NO2 emission were observed for the platinumcatalyzed DPF system from Engelhard. Consequently,

personal exposures to NO2 should be closely monitored. More details on the results of emissions measurements are available in Stachulak et al. 2005a.

3.4 Durability and reliability of DPF systems

One of the DPF systems from ECS, and the systems

from Johnson Matthey and Engelhard accumulated

over 2000 hours of operation. Tailpipe emissions measurements verified their durability. The other system

from ECS failed after approximately 870 hours of

operation due to human error. The initial round of

emissions testing revealed deficiencies in the Oberland Mangold system design, and it was consequently

removed from the vehicle. The DPF systems installed

on the Kubota tractors accumulated somewhat less

operating time due to lower utilization of those vehicles. The active systems from DCL (∼730 hours)

and ECS/Unikat (∼460 hours) proved to be durable

and reliable. The ECS/3M system (∼430 hours) was

replaced with ECS/Unikat systems after 3M decided

to stop supplying their wound fiber filter media. It is

crucial to have equipment suppliers committed to an

on-going maintenance and service issues.

Close attention should be given to the design, specifications, and installation of auxiliary equipment for

the DPF systems. Such equipment including electrical

circuits, fuses, heating elements, timers, air flow controllers, fuel-borne catalyst dosing systems and diesel

burner and other special equipment often required special attention to ensure that Canadian standards for

safety were met, that consumables could be purchased

easily, and that maintenance was straight-forward.

The reliability of vehicle-mounted air compressors

and air pumps on active systems was found to be poor.

When possible, compressors and pumps on a vehicle

should be replaced by compressed mine air with the

moisture removed using conventional moisture separators. Flow rates of the air supply during active

regeneration using electric heating elements were

found to play an important role in regeneration process. Excessive air flow can reduce the temperatures

being attained and adversely affect the regeneration

147
process. Therefore, air flows should be periodically

verified and adjusted if needed.

3.5 Installation of DPF systems

The project offered an opportunity to investigate several issues related to the installation of DPF systems

on underground mining equipment. Ideally, the operation of DPF systems should be transparent to the

vehicle’s operator and should require minimum additional maintenance effort. The DPF systems evaluated

in this study did not meet this ideal situation. In general, tested systems required a relatively high level of

operator attention and engagement from maintenance

personnel. Some of the systems proved to be particularly complex and demanding. Some of the technical

problems with those systems can be attributed to the

fact that manufacturers had limited experience with

deploying their products to underground applications

and used this study as a platform for development and

optimization of their systems.

All of the DPF systems tested on the relatively large

LHD vehicles were successfully installed in the engine

compartments of those vehicles. It was important to

consider all potential problems associated with installation and engine maintenance. Installation of DPF

systems on Kubota tractors was somewhat more challenging. The systems on the tractors were installed on

the front fenders outside of the engine compartment.

Continuous monitoring and recording temperature

and engine backpressure was found to be a very useful

tool.The continuous and instantaneous information on

engine backpressure proved to be valuable for diagnostics of regeneration and overall performance of

DPF system. A redundant system with simple, but

effective, dashboard alarm signal is needed in order

to give information to the vehicle operator about the

engine backpressure. Operators must be attentive to

non-conventional alerts and alarms for high backpressure or else serious harm could be done to the engine.

Analyzing temperature and engine backpressure data

requires expertise and time. For proven DPF systems,

the data need only be collected at a minimum frequency so as to minimize the time spent processing

and analyzing data.

Thermal insulation of exhaust pipes and filters,

where possible, was found to be effective in improving

DPF performances. The length of exhaust manifolds

and number of bends were minimized for optimum

performance.

Using shock absorbing mounts on the DPF assembly was found to improve the durability of the systems.

Mounting DPF system high on a vehicle was found

to reduce potential damage from the intrusion of mud

and water in the DPF housing. An incident with an

LHD which was used for cleaning sumps showed that

mud and water can compromise performance of the

filter element and electrical connections. An alternative to elevating the complete system is designing an

enclosure or redesigning the DPF system so that the

electrical heater is not part of the system, but can be

quickly installed when regeneration is needed.

It is important to install the DPF system components

and associated exhaust manifolds at a safe distance

from fire suppression actuators on the vehicle. A fire

suppression system on one of the evaluated vehicles

was actuated as a result of temperatures generated from

an exhaust manifold that was routed too close to the

actuator by mistake.

The operation of the engine with an overloaded DPF

system might cause serious damage to the DPF system

and engine. The ideal solution would be integration of

the DPF system sensors into an electronic control module (ECM) of electronically-controlled engines and

thus would allow engine output to be limited when

excessive engine backpressure is sensed. This option

needs to be explored with engine manufacturers.

The use of metal electrical connector housings

instead of the often supplied plastic housings was

found to improve their ruggedness, resulting in fewer

maintenance problems.

3.6 Operation of DPF systems

This project showed that an emissions/maintenance

program is essential for implementation and operation of DPF systems. The performance of DPF systems should be evaluated as part of routine preventive

maintenance (Stachulak et al. 2005b).The portable gas

analyzers, such as those from ECOM America used

in this study, were found to be helpful in performing

diagnostics on DPF systems. These measurements are

most effectively carried out by skilled mechanics during scheduled vehicle maintenance, and it is relatively

easy to include this in routine vehicle servicing. Education and training of maintenance personnel in the

specifics of each DPF system plays an important role

in the process.

Proper education of vehicle operators, mechanics

and others involved with DPF systems implementation

and operation is essential for their successful, longterm use.

ACKNOWLEDGMENTS

The authors would like to express their gratitude to the

DEEP consortium for funding the project, and particularly to the members of its Technical Committee.

Also, recognition is due to the Ontario Workers Safety

and Insurance Board and the New Brunswick Workplace Health, Safety and Compensation Commission

for their funding support of the project. An enormous number of people assisted the project, including

148
Andreas Mayer and Paul Nothinger of Switzerland,

Sean McGinn,WinWatts, Michel Grenier, Bill Howell

and DPF system/diesel engine manufacturers. A very

large team of employees at Inco contributed to the success of the project including vehicle operators, maintenance and instrumentation personnel, along with

shift supervisors and foremen. Acknowledgement

is also given to the Stobie Mine manager, Mike

McFarlane, to senior mine personnel Greg Nault and

Rick Mayotte. Special thanks to Giles Bedard, Bob

Coupal and the other members of Stobie DEEP Team

as well as to the Ontario Division of Inco for their

support and encouragement.

REFERENCES

Burtscher, H. 2005. Physical characterization of particulate

emissions from diesel engines: a review. Aerosol Science,

36, pp. 896–932.

Kittelson, D.B. 1998. Engines and nanoparticles: A review.

J. Aerosol Sci. Vol 29. No. 5/6, pp. 575–588.

Mayer,A., Heeb, N., Czerwinski, J., andWyser, M. 2002. Secondary Emissions from catalytic active particle filter systems. Society of Automotive Engineers. 2003-01-0291.

Mayer, A., Matter, U., Scheidegger, G., Czerwinski, J.,

Wyser, M., Kieser, D., and Weidhofer, J. 1998. VERT:

Diesel nano-particulate emissions: Properties and reduction strategies. Society of Automotive Engineers 980539,

pp. 127–138.

Mayer, A., Matter, U., Scheidegger G., Czerwinski, J., Wyser,

M., Kieser, D., andWeidhofer, J. 1999. Particulate traps for

retrofitting construction site engines. VERT: Final measurements and implementation. Society of Automotive

Engineers. 1999-01-0116, pp. 107–121.

Mayer, A. 2000. Datalogging review, Trap Selection and in

Mine trapTest Planning.Workshop on DEEP/Inco in Mine

Test at Stobie Mine, Nov.

McGinn, S. 2004. Noranda Inc.- Brunswick Mine Diesel

Particulate Filter (DPF) Field Study, Final Report of Investigation to the Diesel Emissions Evaluation Program.

[http://www.deep.org/reports/nordpf_final.pdf ].

McKinnon, D.L.,Wheeland, K.G., and Gavel, K. 1989. Diesel

Particulate Filter Underground Trial at Brunswick Mining and Smelting’s No. 12 Mine. SAE Tech. Paper Ser.

891846.

Rubeli, B., Gangal, M., Butler, K., and Aldred, W. 2003.

Evaluation of the Contribution of Light-duty Vehicles to

the Underground Atmosphere Diesel Emissions Burden,

Phase II. Final Report to Diesel Emissions Evaluation

Program. [http://www.deep.org/reports/ldv2.pdf ].

SAEFL 2003. VERT filter list: Tested and approved particle

trap systems for retrofitting diesel engines. Swiss Agency

for Environment, Forest and Landscape (SAEFL), Bern,

June.

Schnakenberg, G.H. Jr. and Bugarski, A. 2002. Review of

Technology Available to the Underground Mining Industry for Control of Diesel Emissions. U.S. Department

of Health and Human Services Information Circular

IC 9262. [http://www.cdc.gov/niosh/mining/pubs/pdfs/

ic9462.pdf ].

Stachulak, J.S., Diesel Emission Control Strategy 2003.

NIOSH Mining: Workshop on Diesel Emissions Control

Technologies in Metal/Nonmetal Mines/CDC/NIOSH,

U.S.A; Cincinnati, Ohio, Feb. 27 and Salt Lake City, Utah,

Mar. 4.

Conard, B.R., Stachulak, J.S. 2000. Underground Evaluation

of Diesel Particulate Filter Systems at Inco’s Stobie Mine.

Proceedings of the Ventilation 2000, 6th International

Symposium on Ventilation for Contaminant Control,

Helsinki, Finland, June 4–7.

Stachulak, J.S, Conard. B.R. 2001. Diesel Emission Controls

strategy: Underground Evaluation of Particulate Filter

System at Inco’s Stobie Mine. Proceedings of Seventh

International Mine Ventilation Congress, Cracow, Poland,

June 17–22.

Stachulak, J.S., Conard, B.R., Bugarski, A.D., and

Schnakenberg, G.H. Jr. 2005a. Long–Term Evaluation

of Diesel Particulate Filter Systems at Inco’s Stobie

Mine. Proceedings of 8th International Mine Ventilation

Congress, Brisbane, Queensland, Australia, July 6–8.

Stachulak, J.S., Conard, B.R., Nault, G., Bugarski, A.D., and

Schnakenberg, G.H., Jr. 2005b. Evaluation and Experience with Particulate Filter Systems at Inco. Mining

Diesel Emission Conference, Toronto/Markham, Ontario.

Canada, Oct.12–14.

149