Diapositive 1

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Lessons learnt from three massive sulphides test
sites Li Zhen Cheng, Denis Bois, UQAT Michel
Chouteau, Ecole Polytechnique Michel Allard,
Noranda (now is Xstrata) David Fountain, Richard
S. Smith, Jean Lemieux, Marc A. Vallee, Fugro
Airborne Surveys Pierre Keating, GSC
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pH 2.3
Aldermac
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• Summary
• Iso-New Insco simple geometry in a resistive
  host
• Test the performance of MEGATEM system.
• Gallen Main body mined out and
  residual massive sulphides are submerged
  in acidic water with surrounded metal fence.
• Look at the impact from these unfavourable
  conditions to AEM surveys.
• Aldermac small and deep pods under
  tailing dump in a hydrographic basin -
  conductive overburden.
• Challenge for MEGATEM system?

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What have been done?

• Field tests
• Two base frequencies of 90 Hz and 30 Hz
• Height attenuation tests
• Reverse flight direction tests
• Transmitter off
• Research
• Data processing visualization
• Anomalies classification
• Modeling and interpretation

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What we have learnt?
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MEGATEM flights over Iso deposit at different
altitudes (line 100501)
35000 fT
35000 fT
461 m
461 m
Bx
Bz
35000
35000
371 m
371 m
35000
35000
274 m
274 m
100000
100000
187 m
187 m
300000
300000
122 m
122 m
250 m
250 m
500 m
500 m
750 m
750 m
1000 m
1000 m
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channel 6
channel 20
channel 6
overburden conductance 1.2 S
channel 20
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In the down-dip direction
In the up-dip direction
Bx
Bx
By
By
Bz
Bz
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X
up - dip
down - dip
Z
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a
b
c
d
X old
X new
Z old
Z new
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3D modeling tools for EM data interpretation

• Maxwell
• Plate
• LeroiAir
• Emigma
• MacroAir
• ArjunaAir
• EmQ
• LokiAir

(EMIT_Au)
(U_Toronto)
Thin sheet
Polyhedron
(PetRos_EiKon)
Prism
(CSIRO_Au)
2.5 D
Sphere
(GSS_Au)
3 D
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30 S
20 S
55 S
40 S
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Gallen deposit
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Gallen deposit
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Aldermac deposit
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Aldermac deposit
Line 401
Line 501
measured
measured
measured
measured
10000 pT/s
dBx/dt
dBx/dt
0
Thick prism
Thick prism
10000 pT/s
dBz/dt
dBz/dt
0
Thick prism
Thick prism
0
0
3 km
3 km
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Conclusion The present project to enhance the
MEGATEM technology has been a successful
collaboration between universities and industry.
New objective Develop new interpretation tools
for geophysical exploration methods