Ventilation Requirements for Uranium Mines

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Ventilation Requirements for Uranium Mines Rabbit
Lake Operation
Presented by Cristian Gherghel, P. Eng. Mine
Engineer, Eagle Point Mine
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Outline

• Introduction
• Ventilation Design Factors
• Ventilation Planning at Rabbit Lake Operation
• The Rabbit Lake Ventilation System
• Ventilation Management and Operating Practices
• Daily Operating Inspections
• Ventilation Surveys and Gas Monitoring
• Continuous Working Level Monitors
• Auxiliary ventilation
• Operating Practices for ore development and
  Production

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Rabbit Lake Operation
Rabbit Lake Operation Location Map
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Introduction - Mine Portal

• Reserves 19.1 million lbs U3O8
• 2006 Production 5.1 million lbs

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Introduction - Eagle Point Mine
Mine Portal
03 Zone
E.A.R
E.A.R
E.A.R.
040 Zone
Granitoid
Dome
Meta
Sediments
1000m
Main Decline
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Introduction Protecting Worker Exposure
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Introduction - Protecting Worker Exposure -
Radiation Protection
Challenges for ventilation engineer

• Dilute radon progeny to maximum exposure of 4 WLM
• Maintain radon progeny below 0.1 WL in working
  areas
• Reduce radon gas exposure limit new monitoring
  system
• Train underground personnel in the importance of
  proper ventilation

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Introduction Ventilation planning

• Single pass ventilation
• Proper sequencing of the development and the
  stopes

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Ventilation Design Factors

• Diesel emission
• Flexibility
• Single pass ventilation
• Retreat mining method
• Fresh air mining workings in waste rock
• Sealing old working areas to minimize leakage
• Water grouting

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Ventilation Design Factors

• Flexibility to adapt to the mining conditions
  O3 zone water inflow

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Ventilation Design Factors
Dividing mining areas in ventilation blocks
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Eagle Point Mine Ventilation System
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Ventilation planning - Eagle Point U/G Mine
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Ventilation Planning - Longhole Stoping
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Ventilation planning typical stope design
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Ventilation Planning - SBM drilling
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Ventilation planning - Longhole Drilling
workers on fresh air in the overcut drift
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Ventilation planning - modeling
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Ventilation Management

• Ventilation Management Procedure

• Ventilation surveys
• Vent Directives
• Auxiliary ventilation
• Sumps, Remucks and TTA
• Underduct flows
• Access in the levels from the main ramp
• Minimum flows required
• Main fans failure

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Vent surveys

• Weekly Volumetric Vent surveys
• Pressure surveys
• Gas monitoring CO, CO2, NO2, 02

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Ventilation Management
Radiation Code of Practice

• Radon progeny
• Radon gas

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Radon Progeny

• Working level ranges for alphanuclear prism
  lights.
• Prism Light Range
• Green 0.10 WL
• Green Amber 0.11 to 0.25 WL
• Amber 0.25 to 0.50 WL
• Amber Red 0.51 to 1.00 WL
• Red or Red with white strobe gt1.0 WL

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Radon Gas

• Code of Practice for Radon Gas
• Prism Light Range
• Green 3,000 Bq/m3
• Green Amber 3,000 to 15,000 Bq/m3
• Amber 15,000 to 50,000 Bq/m3 (RWP and signs)
• Amber Red 50,000 to 60,000 Bq/m3
• Red gt60,000 Bq/m3

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Monitoring

• Daily WL readings
• Gamma Surveys
• Time cards
• T.L.D. badges DRDs
• Personal Dust Pumps
• PADs (for underground)
• Alpha Nuclear Monitors (cam)
• Bio-assay sampling

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Monitoring TLD and DRD

• T.L.D. Badges
• Thermo-luminescent Dosimeters
• records actual exposure to Gamma
• and Beta radiation
• National Dose Registry
• DRDs
• - Direct Reading Dosimeters
• - Shows gamma dose for period worn
• - Counts are recorded daily

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Monitoring - PAD

• PADs
• Personal Alpha Dosimeters
• Worn by all underground personnel (daily)
• Measures Alpha exposure and LLRD for the month
  period
• Loss or contamination requires immediate
  reporting
• Must be recharged daily

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Monitoring - Prisms

• Alpha Nuclear Monitors
• Continuous air samplers
• Measures Alpha activity
• Has a 10 minute cycle
• Working levels are displayed as colored lights
• Follows Code of Practice Levels
• Red leave area immediately

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Operating practices

• Single pass ventilation
• Shotcreting Gamma radiation below 10 microSV/h
• Shotcreting Applied remotely
• Stope mucking Remote control scooptram
• Sill covered with crushed rock min 30 cm
• Push auxiliary ventilation system
• Water grouting
• Sump, TTA and remucks under negative pressure
• Vent tubing minimum 30 m from the face

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Operating practices
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Conclusions

• Eagle Point Mine effective management program
• Key practices
• proper monitoring of the ventilation system in
  all stages
• effective control of the radiation sources
• a proactive attitude

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Questions?