Managing Heat Exposure in Canada’s Underground Mines

1. MMSL Technical Workshop – March 25 – 26, 2010 Managing Heat Exposure in Canada’s Underground Mines Steve Hardcastle RC 140 – Underground Mine Environment

2. Presentation Outline • Acknowledgements • Introduction • Impact • Research Objectives • Research Methodology • Results • Interpretation and Discussion • Other Work • Conclusion/Recommendations • Next Steps

3. Acknowledgements • Deep Mining Research Consortium (Agnico-Eagle, Barrick Gold, Xstrata, Goldcorp, Vale Inco, Rio Tinto, Industry Canada, Ontario’s Northern Development and Mines, City of Greater Sudbury) • University of Ottawa (Drs Glen Kenny & Frank Reardon, Research Associates and test subjects) • Agnico Eagle, Vale Inco, Xstrata Nickel, FNX Mining (Provision of test sites and subjects) • Mines and Aggregates Safety and Health Association’s Ontario Mine Rescue Program • WSIB, NSERC, University of Ottawa Research Chair, Canada Foundation for Innovation (Parallel funding) • Kevin Butler, Charles Kocsis, Gary Li (MMSL Staff)

4. Introduction • The research is comprised of a suite of projects performed by the University of Ottawa and CANMET-MMSL in co-operation with the mining industry and safety agencies. • The issue, with a changing surface climate, greater depth and continued mechanization using larger equipment, Canadian underground mine workers have an increasing risk to be exposed to heat stress • This is not only a health and safety issue for the worker but also a productivity and cost issue for the mining company. • Reducing exposure time limits productivity and changing the thermal environment is expensive

5. Impact Program Activity Architecture (PAA) 1.1.1 Innov. & Prod. – 20% 2.2.1 Strong Env. Perf. – 30% 3.1.1 Mining Safety – 50% • Mining safety may seem to be the driving factor but how heat is managed affects productivity and a mine’s environmental impact • To combat heat you either need more air or chilled air both can be multi-$M investments and consume significant power that produce GHGs. • Reducing productive face time affects profitability. Improved guidelines and methods to determine ventilation volumes and refrigeration can increase productivity and help competitiveness.

6. Research Objectives • Due to the cost and safety issues, industry, workers and regulatory agencies need a better understanding of what are the causal factors contributing to heat stress in mines and how they can be managed • Analyze mining activity and conditions • Simulate under controlled laboratory conditions (current & future – adverse) • Explore clothing, age, fitness, work practices • Evaluate current management practices and exposure monitoring • Develop more appropriate guidelines and mitigating strategies

7. Research Methodology Four aspects of the physiological research • Laboratory Task Simulation • Mine Rescue Assessment • Clothing • Work : Recovery Exposure Management Protocols

8. Research - Task Analysis • Equipment – Physiological Testing Skin / Core Temperatures O2 / Energy Consumption Heat Production/ Storage

9. Research - Task Analysis • Experimental procedures - Example • The Movements (Tasks)T#1: Sitting T#2: Treadmill (legs)T#3: Pulleys (arms) T#4= T#2 + T#3 • Schedule - Occupation 1 (Bolting) T#2 (4 min), T#1 (3 min), T#4 (9 min), T#2 (1 min), T#4 (48 min), T#1 (1 min), T#4 (2 min), T#1 (16 min), T#4 (29 min), T#2 (7 min). • Similar schedules for 3 other occupational groups • Simulations under “normal” and “adverse” environmental conditions Miner Work Simulation

10. 30ºC 60RH 35ºC 60RH 39ºC 60RH 35ºC 40RH 35ºC 80RH Results – Adverse Conditions Subjects unable to complete test Environment 38.5 CoreLimit 38.0 37.5 Rectal Temperature (ºC) Work 1: 386 W 2: 360 W 37.0 3: 345 W 4: 227 W 1 2 3 6 4 5 5: 365 W 36.5 6: 285 W 0 20 40 60 80 100 120 Time (min)

11. Research – Upper Limit • Extreme Task – Mine Rescue 10 Subjects Average SD Age (yrs) 25 - 62 47 9 Height (m) 1.78 0.07 Weight, Semi-nude (kg) 87.4 12.1 Body Fat (%) 19.7 3.9 Equipment (kg) 21.9 1.7

12. Research - Upper Work Limit • Rescue Team 4 + 1 Simulated ExerciseRepeated 5 times • Loads: 25-155 kg • Incline: 0-20% • Distance: 0-250 m • Temperature:< 20C • Work: 400-750W • 5 Ramp & 2 Level Elements • Duration 65 mins

13. 38.2 680 ) ºC ( 38.0 600 37.8 520 Average Core Temperature 37.6 440 37.4 360 ) 2 37.2 280 Energy (W/m 37.0 200 36.8 120 0 10 20 30 40 50 60 70 Elapsed Time (min) Results – Rescuers already at risk • 5 Tests x 2 Subjects • 3 subjects >38C within 20 – 50 min. • Environment very cool compared to a deep mine • Clothing limits evaporation of sweat / promotes heat storage Continuous increase No recovery at lighter work rates

14. Research – Clothing Properties • Evaluating the human/clothing system WickingUndergarment CoverallsFull PPE Work PantWicking T-Shirt

15. Research – Clothing Phase 1 Initial Tests performed under abstract conditions to isolate benefits of specific clothing ensembles • Test in hot and dry to maximize evaporation potential • Limit air velocity to avoid discomfort during the recovery period. • Choose “heavy” work rate: cycling @ 400 W, to generate a high heat load/greatest cooling potential across clothing • 5 clothing ensembles including semi-nude control • 8 subjects tested under each condition • 60-minutes of work, 60-minutes of recovery

16. Control - Shorts Mine gear only Undergarment only 1.0 Mine gear + undergarment 37.66ºC 0.8 0.6 Esophageal Temperature (ºC) 0.4 0.2 37.25ºC Exercise Recovery 0.0 0 15 30 45 60 75 90 105 120 Time (min) -0.2 Results - Clothing • Change in core temperature • Less heat loss with coveralls causes core temperature to continually rise • Sportswear similar to being naked • Coveralls store more heat when resting • Note length of recovery decay and residual heat

17. Research – Heat Storage/Recovery Other research has shown heat to be cumulatively stored with each repeated work session. Tests performed in University of Ottawa’s calorimeter • Same level of exercise (360W) used throughout • 4 trials of 8 subjects, random order • The environmental temperature is increased through Trials 1 to 4, from 28 to 31.5C wet-bulb • Work duration and recovery adjusted as temperature increased, from 100% work, through 75:25, 50:50 and 25:75 work/recovery regimes • Subjects wore work-pants, wicking t-shirt and full mine PPE

18. Results – Protocol Increasingly over-protective • 120 mins of continuous work completed without exceeding 38C • Final core temperature decrease through trials • Recovery period more than compensates for the higher environmental temperature Trial 1 Trial 2 Trial 3 Trial 4 38.2 38.0 37.8 37.6 Rectal Temperature (°C) 37.4 37.2 37.0 0 15 30 45 60 75 90 105 120 Time (min)

19. Interpretation and Discussion • Results shown are snap-shots • The body of data needs to be assessed en masse • Other issues/avenues of research • Age/Fitness • Wind speed • Hydration • Increased air density at depth • Optimum recovery time • Improved work:rest protocols

20. Other Work – CANMET Roles • CANMET-MMSL are not only responsible for managing & advising in the heat stress research. • It has had specific responsibilities to evaluate the suitability of instrumentsused to assess the thermal environment – these are what the industry will use to determine acceptability • It has also helped identify why it can become hot underground and how it could be addressed – it may be a very simple ventilation solution • It has also been tasked with the University of Ottawa to produce a non-medical handbook

21. Conclusions/Recommendations • This research has benefited from the use of the University of Ottawa’s calorimeter. • Nobody else has, or has had, a similar Gold Standard facility to truly investigate heat stress. • This research thrust has generated a significant amount of useful data during the last 5 years. • The industry’s present interest is now to communicate this science and to develop better heat management strategies. • This work could also help modify the current regulations to something more scientifically based.

22. Next Steps • Complete current testing schedule • Communicate the science to the client • CIM presentations, Ventilation Symposium Workshop • Continue with Peer reviewed publications, these are needed to facilitate any change in regulations or to adopt something different • Support the harmonization of regulations and delivering a common scientifically founded message through the available guidelines • Seeking funding/support for the additional issues

23. Questions?