Gabriel ARPA, Kyuro SASAKI and Yuichi SUGAI

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KAINANTU UNDERGROUND MINE STOPE VENTILATION
MEASUREMENT USING TRACER GAS AND NUMERICAL
SIMULATION

• Gabriel ARPA, Kyuro SASAKI and Yuichi SUGAI
• Department of Earth Resources Engineering,Faculty
  of Engineering, Kyushu University, Fukuoka
  812-8581, Japan

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BACKGROUND
Continuous research into improving airflow
quality and quantity is an on going activity.
Tracer gas can be an effective method to assess
mine ventilation system.
Tracer gas can be used to
Determine complex airflow patterns and flow
volume, where velocity is too low, openings too
large, or cross section geometry too
complex. Accurate determination of ventilation
assessment parameters
Re-circulations, - Leakages, -residence
time Simulate and model the spread of
contaminants.
Tracer gas can give effective information of
airflow in highly irregular airflow paths and can
be an effective method to assess mine ventilation
system and airflow dynamics.
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REVIEW
1.Check for air Leakage. (Hardcastle et al. 1993)
However, there is little research on shorter mine
airways and mine face, and the effect of dead
ends and open spaces along airway routes.
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OBJECTIVE
To Study Airflow through narrow vein shrinkage
stope by using tracer gas technique and numerical
simulation. The effect of dead end drives,
openings and empty spaces along the airway route
on airflow quantity and quality.
METHOD
By pulse injection of SF6 from upstream positions
and measure the concentration with elapsed time
at a downstream position.
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RESEARCH APPROACH
Ventilation Survey Tracer Gas Measurement Numeri
cal Simulation
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FIELD MEASUREMENT
The Kainantu Mine
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KAINANTU MINE OVERVIEW
Mining Method Narrow Vein Shrinkage stope
Production 300 ton ore/day
Semi-mechanized operation
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MINE VENTILATION
Ascension Through flow system
Fan 3
Fan 2
Fan 1
4th Outlet
Main intake (1300 Portal)
Schematic of ventilation system
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MEASUREMENT SYSTEM
Gas Monitor system
Lap top Stop watch Portable scale Balloons Sulfur
hexafluoride (SF6)
Photoacoustic gas monitor (Brual Kjear 1302)
Resolution 10 ppb
Absolute accuracy /- 50 ppb
Sampling rate 40 sec
Not to scale
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MEASUREMENT PROCEDURE
Drives
3 m
4 m
Raises
1 m
1 m
SF6 release and measurement stope 20L20R (
Shrinkage stope)
SF6 release and measurement stope 20L24R (
Shrinkage stope)
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NUMERICAL SIMULATION
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EFFECT OF DEAD SPACES OPENING ON AIRLOW
Airways with dead spaces
Airways without dead spaces
Conc.
Time
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RESULTS
54 m3/min
31 m3/min
Level 20
SF6 release and measurement stope 20L20R (
Shrinkage stope)
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RESULTS
30 m
70 m
SF6 release and measurement stope 20L24R (
Shrinkage stope)
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RESULTS
SF6 release and measurement stope 19L16R (
Shrinkage stope)
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RESULTS
Better air flow in the stope with one raised,
then the stopes with both raises open.
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DISCUSSION and CONCLUSION
Better understanding of airflow routes can be
achieved by studying the arrival times and the
peak of the concentration time curve for the
various routes simulated.
Airflow rates of the stopes were evaluated with
matching measured concentration-time curves with
numerical ones by a numerical diffusion model in
considering diffusion in open and empty spaces
Most importantly, an additional airway branch was
constructed. The additional branch in the
numerical model has a much longer airway length
and an increased cross-sectional area with low
air flow velocity. The new method has greatly
improved the tailing effect .
Therefore it can be concluded that openings, dead
end drives and other open spaces have no relation
on flow rates, but affect the airflow quality
provided from the inlet portal
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END OF PRESENTATION!!! THANK YOU VERY MUCH FOR
YOUR KIND ATTENTION!!!!!!!!!!
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RESULTS
Additional airflow route to simulate for open
spaces, dead end drive, voids etc..
Schematic of airflow. A) Plan of 20 level, B)
Arrangement of additional branch (Route 3)
SF6 release and measurement stope 20L20R (
Shrinkage stope)
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RESULTS
Additional airflow route to simulate for open
spaces, dead end drive, voids etc..
Schematic of airflow. A) Plan of 20 level, B)
Arrangement of additional branch (Route 3)
30 m
70 m
SF6 release and measurement stope 20L24R (
Shrinkage stope)
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RESULTS
Additional airflow route to simulate for open
spaces, dead end drive, voids etc..
Schematic of airflow. A) Plan of 20 level, B)
Arrangement of additional branch (Route 3)
30 m
70 m
SF6 release and measurement stope 19L16R (
Shrinkage stope)
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Stope 20L20R
Stope 20L24R
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Most importantly, improvement has been made at
the tailing effect between the simulation and
tracer gas measurement by reconstructing an
additional branch to represent the delayed
arrival of air due to the open spaces along the
airways. The additional branch in the numerical
model has a much longer airway length and an
increased cross-sectional area with low air flow
velocity. Therefore it can be concluded that
openings, dead end drives and other open spaces
have no relation on flow rates, but affect the
airflow quality provided from the inlet portal.
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VENTILATION NETWORK
19L16R
20L20R
20L24R
Construction of entire ventilation network using
Mine ventilation simulator, MIVENA Ver.6 (Sasaki
Dindiwe, 2002)
Kainantu ventilation network (MIVENA)
Datadase window
Analysis window
Kainantu ventilation layout
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Normal Leak