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

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Presentation on theme: "Validation of the Ventgraph Program for use in Metal/Non- Metal Mines Christopher Pritchard MS P.E. Mining Engineer NIOSH OMSHR Spokane, WA."— Presentation transcript:

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 –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 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 entranceWorkings

11 Sunshine Pictures 10 Shaft Hoist at 3100 Level Stope

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

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

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

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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 m 3 /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?


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