3D induction: fact or fiction?
Do we need to worry about 3D induction for mining scale problems?
3D induction in an isolated body of limited frequency range
Canadian generic EM ore body
2D response: centre site
2D inversion of �perfect� 2D data
2D cf. 3D response: centre site Mackie
3D comparison: centre site Mackie SYSEM (IE) EMIGMA (ILN)
2D cf. 3D response: centre site EMIGMA (ILN)
2D cf. 3D response: centre site EMIGMA �new�
2D cf. 3D response: centre site Mackie �new�
TM Rho_a comparison
TE Rho_a comparison
2D inversion of EMIGMA 3D data
Example: Okak Bay project
Large aeromag anomaly
Raw rho_a_av map @ 192 Hz
Borehole intersections
Inversion of Line 6
Strike & distortion analysis
Distortion & anisotropy-corrected data
TE rho_a map @ 192 Hz
Real IV @ 500 Hz
1D inversion of site GAL004 data
2D inversion of Line 6
2D inversions of all lines
2D inversion of line Z
Pseudo-3D images from 2D inversions
Pseudo-3D model space: cutout
Pseudo-3D model space: projection
Pseudo-3D model space: body volume
Non-inductive response: Why?
Non-inductive response: Region of anomaly
Regional 3D currents - local charges?
EMIGMA modelling:
Conclusions - 1
Conclusions - 2
Conclusions - 3
Recommendations
Acknowledgements
Email: [email protected]
Home Page: www.cg.nrcan.gc.ca/staff/jones
Other information: Presentation given at 3D-EM II workshop in Salt Lake City on 27-29 October, 1999.