1. Validation of the Ventgraph Program for use in Metal/Non-Metal Mines
Christopher Pritchard MS P.E.
Mining Engineer
NIOSH OMSHR Spokane, WA

2. Summary Introduction Description of 1972 Sunshine Mine and Fire Event
Recreating the ventilation network
Modeling network and mine fire
Model verification
“What If” Scenarios
Summary and Conclusions

3. Introduction NIOSH Research Plan - 2008
Reduce incidents and severity of fires in M/NM Mines
Increase understanding of products of combustion
Improve ventilation and escape planning
Investigate and choose ventilation software
Verify by using actual M/NM mine fire incident

4. Ventilation Software Requirements
Mine Fire simulation capabilities
Real time
Non-compressible flow
NVP
Graphics
Choice: Ventgraph for Windows

5. Fire: 1972 Sunshine Mine Historically significant Deep
Complicated ventilation system
Compressed air injection
Multiple fans
Drastic changes to ventilation system

6. Previous Sunshine Work:
1977 USBM Report: Hall/Ramani/Greuer
Network model only
Semi NVP
No fire
No contaminants
No graphics

7. Sunshine Ventilation System

8. 1972 Fire Event 11:40 am Smoke detected 3700L @ No. 10 Shaft
12:00 Mine evacuation begun by 3100L route, surface notified, 3700L fire door closed at Jewell Shaft
12:45 last survivors hoisted to SH, 1:00 last hoist run.
1:15 No. 12 SH cover removed

9. Fire and Evacuation Sequence

10. Sunshine Pictures
Jewell Shaft entrance
Workings

11. Sunshine Pictures
Stope
10 Shaft Hoist at 3100 Level

12. Sunshine Pictures No. 8 Shop area – smoke detected
“Blue Room” 3700 Level

13. Sunshine Pictures
3700 Level 910R fire site
Fire Site in raise

14. Modeling Process Airway data from 1977 USBM report
Scale airways from JW Andrews Sunshine maps
Temperature data from USBM vent survey – Fall, 1971
Barometric data from mine elevations

15. Modeling Development Initial run – 1.6% accuracy with USBM
Fire location – 910 Raise between 3100 and 3700 level
Bulkhead failure sequence
Problem with 3400 booster fan, redo with fan curve, 3.3% accuracy

16. Calibrate Model to Fire Events
Key events:
11:35 am Smoke 3700 level
12:00 smoke observed at surface
12:10 smoke leaks into 3100 level

17. Fire Model Events Fire sequence model:
11:05 am wood fire 910R, 65m long, ramp up time 5 minutes to Level 10
11:10 fire to 100m, 910R Bulkhead partially failed, 08 Shop door open
11:15 fire to 200m, 910R BH further failure
11:20 fire constant, 910R BH wide open

19. Ventgraph Output
Smoke at approximate time of discovery 11:40 am

20. Ventgraph Output
Local Detail of Fire Area – CO Levels at 11:40 am

21. Verification Model - good correlation to observed smoke arrival times
CO levels correlate well to escaping miner behavior
Results of model give confidence to analyzing alternatives
Run “What-If” Scenarios

22. What-If Scenarios Turn off 3400 Level Booster Fans
Problem with implementation of task
“What-If”: Stop fan 12:35 pm
Clears most 3100 roadway in 15 min
CO still high at 3100L hoist for 80 min
Did not effect lower mine CO levels
Would more 12:45 cage miners survive?
Allow rescuers to reach 3100L hoist more quickly?

23. What-If Scenarios Jewell Fire Door Closure Sequence
Supervisors underground made best decision – close 3700L door.
Close 3100L door – evacuating miners perish, lower levels may survive longer
Best option - leave both doors open and shut down 3400L booster fans

24. What-If Scenarios Opening No. 12 Shaft cover earlier
Slight improvement in airflow to 4800L: 0.9 – 2.1 m3/s
Essentially no difference to any other area of the mine

25. What-If Scenarios Placement of bulkheads Aid fire fighting
Simulation “short term” accurate
Fire can endanger mine infrastructure
Planning may minimize damage
Sunshine: no combo of booster/doors works
Stopping needed to be installed inby 910R (and fire) to be effective

26. Summary/Conclusions Ventgraph validated in Sunshine Scenario NVP
Multiple fans
Leakage
Recirculation
CO levels
Issues/Problems:
Ventgraph fire “Intensity Levels”
Booster fan flow deviation w/USBM model

27. Summary/Conclusions 3400 Level booster fan decision
Contributed to 1977 MSHA ACT
Valuable modeling/training tool
Use before and during event
Survivors
Tom Wilkinson
and
Ron Flory

28. NIOSH - OMSHR Spokane Questions or Comments? CPritchard@cdc.gov