3/7/2011 3/7/2011 VENTILATION SYSTEM DESIGN VENTILATION SYSTEM DESIGN AND COMPUTER SIMULATION AND COMPUTER SIMULATION FOR AN UNDERGROUND METAL MINE FOR AN UNDERGROUND METAL MINE Presented by Presented by Hongliang (Henry) Wang Hongliang (Henry) Wang Newmont USA Limited Newmont USA Limited SME 2011
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SME 2011 Metal Mine Ventilation Design and Simulation Hongliang Wang
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3/7/20113/7/2011
VENTILATION SYSTEM DESIGN VENTILATION SYSTEM DESIGN AND COMPUTER SIMULATION AND COMPUTER SIMULATION
FOR AN UNDERGROUND METAL MINEFOR AN UNDERGROUND METAL MINE
2. Review of Newmont2. Review of Newmont’’s Nevada Underground s Nevada Underground Mines and Mine Ventilation SystemsMines and Mine Ventilation Systems
3. Ventilation System Design and Optimization for 3. Ventilation System Design and Optimization for Exodus ProjectExodus Project
Exodus Project in 2010:Exodus Project in 2010:Continue exploration, start mine development, bring to Continue exploration, start mine development, bring to
production in Q4; production in Q4; and deal with surface mining…
Lantern 3 Pit: 2009~2010
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Mine Designs of Exodus ProjectMine Designs of Exodus Project
redesign with updated block model; redesign with updated block model; ……
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Mine ventilation designsMine ventilation designs
Ventilation for different Stages of Mine Life: Ventilation for different Stages of Mine Life: Exploration, Development, PreExploration, Development, Pre--production, upper level ventilation, production, upper level ventilation, lower level ventilation, future growth;lower level ventilation, future growth;
Ventilation System Selection:Ventilation System Selection:Exhausting vs. Forcing, Shaft vs. RampingExhausting vs. Forcing, Shaft vs. Ramping
Scheduling and sequencing of vent infrastructures:Scheduling and sequencing of vent infrastructures:Ahead of vs. parallel with production;Ahead of vs. parallel with production;Long vent raise vs. short vent raises in series;Long vent raise vs. short vent raises in series;
Surface Mining:Surface Mining:Ramp,Ramp, vent raises and escapeways to the active pit;vent raises and escapeways to the active pit;
Computer Simulation and ventilating design optimization.Computer Simulation and ventilating design optimization.
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2. Nevada Underground Mines Ventilation System Review2. Nevada Underground Mines Ventilation System Review
DPM Compliance:Bio-diesel, new engines,Electric haul trucks…
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Leeville Main FanLeeville Main Fan
2M HP, 700 KCFM
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Greater LeevilleGreater Leeville
Φ 26’~32’ 2100’ deep2.2 MCFM, ~$100M
NEW VENT SHAFT
Production Shaft
Ventilation Shaft
County Road
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•• MidasMidasNEW DEEPINTAKE RAISEΦ12, 1200’
Main DeclineEXHAUST RAISE
EXHAUST RAISE
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•• Chukar Chukar
NEW DECLINE
OLD DECLINE
Original Mine Designs:Two years mine life; three250 HP fan in series.
Mine Life Extension
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•• Deep PostDeep Post
Barrick’s Post Betze Pit
Exhaust Raises
Intake Raises
Main Fans
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Short Summary of the ReviewShort Summary of the Review
Ventilation systems are very expensive, capital and Ventilation systems are very expensive, capital and operating cost are high; ventilation system is difficult to set operating cost are high; ventilation system is difficult to set up or upgrade.up or upgrade.
““Over ventilated ?Over ventilated ?”” not the case in most mines, where not the case in most mines, where operations are fighting hard for ventilation due to poor operations are fighting hard for ventilation due to poor efficiency of fresh air distribution. Ventilation management efficiency of fresh air distribution. Ventilation management plan is critical for mine operations.plan is critical for mine operations.
New DPM regulation adds more challenges to mine New DPM regulation adds more challenges to mine operations, but ventilation improvement is often the ultimate operations, but ventilation improvement is often the ultimate solution.solution.
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Lantern 3 Pit: 2010~2011
3. Exodus Project 3. Exodus Project Mine Ventilation Design Options and Economic AnalysisMine Ventilation Design Options and Economic Analysis
North Lantern
Pit
Decline
Q2: How many reserves we can generate?Q2: How many reserves we can generate?2010MY Model total resource: 2010MY Model total resource: 800,000 ounces; average grade @ 0.25; 800,000 ounces; average grade @ 0.25;
Q1: What is the best way to design the mine?There might be 16 different scenarios: Cut-off grade (Oz/ton): 0.15, 0.18, 0.20, 0.22;Stope width (ft): 15, 20, 25, 30.
Q3: What are the options for ventilation?Q3: What are the options for ventilation?How much air we need, what is the best way How much air we need, what is the best way to establish the vent system so we can start production in Q4? to establish the vent system so we can start production in Q4?
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Stope Design and OptimizationStope Design and Optimization
1
3
2
4
2
3 4
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Mine Ventilation Design Option 1: Deep Vent RaiseMine Ventilation Design Option 1: Deep Vent Raise
TonnageTonnage--Grade Curve of the Block Model: Upside PotentialsGrade Curve of the Block Model: Upside PotentialsExodus Grade-Tonnage Curve (Design Shapes)
0
500,000
1,000,000
1,500,000
2,000,000
2,500,000
0.00 0.05 0.10 0.15 0.20 0.25 0.30
Cutoff Grade
Tons
and
Oun
ces
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
Head
Gra
de (o
z/to
n)
TONS OUNCES GRADE
Case Tons Grade Ounces NPVBase Case @900 1,273,114 0.247 314,479 11,015,807$
Mine Ventilation System Selection: Literature Review Mine Ventilation System Selection: Literature Review
(b) And the following arguments favor a forcing system [1, 2].
• Deliver fresh air to working places, which is desirable for mine ventilation quality control. In exhausting system, intake air gets contaminated by underground traffic.
• Working places are independent of each other. In exhausting system, lower levels get experienced air from top levels.
Based on the location of the main fan(s) in the system.
(a) The following arguments favor an exhaust system [1, 2].
• Utilize haulage or hoisting openings as intakes, which is desirable for mine operations. In forcing system, main haulage route is in exhaust air.
• In case of fire or emergency, the primary escape way is in intake air (depended on the location of fire). In forcing system, the secondary escape way is in fresh air.
[1] Mine ventilation and air conditioning. Howard L. Hartman.[2] Engineering factors in the ventilation of metal mines. G. E. McElroy.
WorkingArea
WorkingArea
Haul R
oad
WorkingArea
Haul R
oad
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Exhausting or Forcing?Exhausting or Forcing?
Main Fan
Haul Road
If the depositgrows significantly
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CFM RequirementCFM RequirementEquipment List and CFM requirements @Equipment List and CFM requirements @150 CFM/HP150 CFM/HP
only top half of the deposit was in only top half of the deposit was in ‘‘reservereserve’’ quality.quality.Ground Condition Uncertainties:Ground Condition Uncertainties:
lack of Geotech information for the locations of the vent raiseslack of Geotech information for the locations of the vent raises..