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Diesel Exhaust Exposure In The MiningEnvironment
Presented by: Sara Lovell, P.Eng.
Occupational Hygiene Consultant
OHAO Fall Symposium
October 24, 2013
Outline
Health effects of diesel exhaust
Ontario Regulatory Requirements
DPM Monitoring Program
Strategies for Control in Mining Environments
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Short term exposureheadache, dizziness, andirritation.
Prolonged exposure canincrease the risk of:
• lung cancer
• cardiovascular,cardiopulmonary andrespiratory disease
Mining Hazard Alert
IARC Classification
In 2012, IARC reclassified Diesel engine exhaust to Group 1, Carcinogenicto Humans
Previously, 1988 Group 2A, Probably Carcinogenic to Humans
Based on sufficient evidence that exposure is associated with increasedrisk of lung cancer
Elevated further the importance of effective exposure assessment andcontrol
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Ontario Regulatory Requirements
Mining and Mining Plants Regulation 854/90
Section 183 addresses the operation of diesel-powered equipment
Sets our requirements for:
Documented procedures
Volume of air flow where equipment operating
Total ventilation requirements for equipment operating normally in asingle continuous course of air
Mechanical ventilation requirements
Flow of air of 0.06 cmps/kw of power of diesel-powered equipmentoperating
Exposure prevention (next slide)
Tests to be conducted including air flow, CO in exhaust gases &atmosphere, other constituents (NO2, formaldehyde, total carbon)
Ontario Regulatory Requirements (cont’d)
Subsection 183.1
(4) The flow of air must reduce the concentration of toxic substances indiesel exhaust emissions to prevent exposure of a worker to a level ofno more than,
(a) the limits prescribed under section 4 of Regulation 833/90,“Control of Exposure to Biological or Chemical Agents”; or
(b) if no limits are prescribed under that section, the threshold limitvalues adopted as criteria or guides under Section 283.
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Ontario Regulatory Requirements (cont’d)
Subsection 183.1
(5) The flow of air must,
(a) reduce the time-weighted average exposure of a worker to totalcarbon to not more than 0.4 milligrams per cubic metre of air; or
(b) reduce the time-weighted average exposure of a worker toelemental carbon, multiplied by 1.3, to not more than 0.4 milligramsper cubic metre of air.
DPM Monitoring Program
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Elements Of A DPM Monitoring Program
Identify Sources – Hot Spots
Know Your Diesel Fleet
Identify Worker Exposures
Validate With Measurements
Keep it simple
Identify Sources – Hot Spots
Observe exposure through visual assessment – walkthrough survey
Review process
Understand where ventilation is most/least effective
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Know Your Diesel Fleet
Which equipment is new / old?
Who are the major contributors?
Observe & understand equipment
Controls currently in place (e.g. DPF,pressurized cabs)
Confirm adherence or define amaintenance program
Identify Worker Exposures
Identify areas with high traffic
Observe habits
Interview workers
Review job tasks – watch them work!
Create similar exposure groups (SEGs)
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Validate With Measurements
Sample workers to refine SEGs
Use direct reading instruments to identify problem spots in the mine andwith equipment
Workplace Evaluation
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Tailpipe & Breathing Zone Evaluation
Measurement at thesource
Measurement in WorkerBreathing Zone
Breathing Zone - NIOSH 5040
Measurement of ElementalCarbon (EC) as a surrogate fordiesel particulate matter usingNIOSH method 5040
Draw a representative quantityof air through a 37 mm quartz-fibre filter using an air samplingpump)
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Breathing Zone - Direct ReadingInstrumentation
Displays EC levels in real time(Flir® Airtec™ is shown)
Uses technology developed byNIOSH to precisely replicateNIOSH 5040 results
Diaphragm pump with a particlesize selector permits thepassage of submicron particlesonly
Tailpipe Emissions (CO)
ECOM EN2 – Tailpipe Emissions Measurement
The Future The Past
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How To Integrate Tailpipe Emissions
Identify high contributors of NO2
and CO
May also indicate high DPMcontributors
Assist in development ofadministrative controls
Draeger EM 200
Controls
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Elimination / Substitution
In underground mines, no feasible fuel substitute for diesel currently
For other mining environments such as open pit, alternatives such asuse of biofuels and cleaner fuel composition exist
Biofuels would DPM and CO; however, NO2 and VOCs
Other power sources possibly? Feasibility?
Elimination / Substitution
Push for “ever cleaner diesel” and application of alternate energies
Rechargeable battery application tested in underground loaders(CanmetMINING reference, NRCan Green Mining Initiative)
Diesel-rechargeable battery
Hydrogen fuel cell-rechargeable battery
Lithium batteries also showing some headway
(http://www.nrcan.gc.ca/minerals-metals/technology/green-mining-initiative/4483)
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Engineering Controls
Effective Ventilation
Ontario regulations very specific regarding requirements
Caution: In some underground settings, higher air velocities mayincrease worker exposure by drying-out and re-suspension / re-entrainment of settled dust
Additional energy costs to heat the air – Northern Climates
Engineering Controls
Ventilated / Filtered Cabs
Diesel Aerosols and Gases in Underground Mines: Guide to Exposure Assessment and Control; NIOSH, 2011
OutsideFiltration
InsideFiltration
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Engineering Controls
Reduction At The Source
Catalytic conversion
Particulate filters – Decrease DPM / Increase NO2
Exhaust Gas Recirculation (EGR) – Controls NO2 through increasedtemperatures and oxygen levels = Potential DPM Increase
Administrative Controls
Modification of work practices to minimize exposures:
Avoid idling
Controlling worker location, not rotation
Limiting number of vehicles per area
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Administrative Controls
Vehicle Maintenance Program
Clean Fuel
Clean Fuel Tanks
Clean Lubricants
Readily Change Lube
Other strategies likely exist
Respiratory Protective Equipment
Last resort, as always
Will require a comprehensiverespiratory protection programand monitoring
CSA Standard Z94.4-11 –Selection, Use and Care ofRespirators
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Auditing the Diesel Emission Control Program
On a regular basis review each element:
Review documentation – is each element being addressed anddocumented
Based on testing (atmospheric, ventilation, worker exposure,vehicle, etc.) do changes need to be made?
Are workers engaged? Do they understand the importance of thecontrols and measures?
Are requirements being communicated in training and in follow upHS meetings or daily safety talks?
Summary
Diesel exhaust, Group 1 IARC Classification as Carcinogenic to Humans
Specific regulatory requirements in Ontario pertaining to diesel-poweredengine operations in mines
To minimize worker exposures, need well defined program including:
Qualitative and quantitative risk assessment
Implemented controls and work procedures (multi-faceted approach )
Communication and training
Effectiveness of program must be monitored
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What’s Next?
What are the opportunities for improvement?
Are we ensuring the protection of miners with regards to exposure control?
Questions?
Thank you!!
