1. Going Deep:
Seismic reflection surveys in exploration -
Project HIRE, Finland
Ilmo Kukkonen
Geological Survey of Finland (GTK)
Espoo, Finland
ilmo.kukkonen@gtk.fi
GeoArena 2012
Uppsala Konsert & Kongress
October 16-17, 2012
Ilmo Kukkonen, Oct 17, 2012 1

2. Why apply reflection seismics in exploration?
Why go deep?
• High spatial resolution of reflection seismics
• Great depth extent without essential decrease in resolution with depth
• Shallow parts of mine camps often explored already
• Mining at shallow depths will eventually lead to mining at deeper levels
• New methods, new views are necessary in exploration
• Active mineral exploration business in Finland, with new mines
opened and planned
•Aims of seismic surveys can be set at:
• Direct detection of deposits
• Tracing structures related to deposits
Crustal structures along FIRE 3, Central Finland
Ilmo Kukkonen, Oct 17, 2012 2

3. Project HIRE of GTK 2007-2011
• 16 target areas in Finland
• 2-d surveys (10-80 line-km/target)
• Vibroseis & explosion sources,
• Total 2D lines 700 line-km
• Targets in exploration claims and mine camps
owned by companies or GTK
• Nuclear waste disposal site
Contractor:
• Vniigeofizika & Machinoimport
Research partner:
• Institute of Seismology, Univ. Helsinki
HIRE expenditures
• Ministry of Labour and economy:
Russian debt conversion to Finland 3.4 M€
• GTK 0.7 M€, companies 0.6 M€
Field work 2007-2008
Processing, interpretation and reporting 2008-2012
Ilmo Kukkonen, Oct 17, 2012 3

4. Today: Two case histories
• Outokumpu Cu-Co-Zn mining and exploration area
• Hannukainen FeOx-Cu-Au mining area
Ilmo Kukkonen, Oct 17, 2012 4

5. Case history 1:
Outokumpu-Polvijärvi Cu-Co-Zn
mining and exploration area
Ilmo Kukkonen, Oct 17, 2012 5

6. The HIRE and FIRE surveys in the Outokumpu ore belt
Birthplace of modern metal
industry in Finland
• Three historical and one
active mine
• Total resources ≥ 50 Mt
massive sulfides (Cu, Co, Zn, Ni, Ag, Au)
FIRE surveys 2002
• FIRE-3 transect
• OKU1, OKU2, OKU3 2002
HIRE surveys 2008
•V1, V2, V3, V7, V8
• E1
• Total of 82 km high
resolution HIRE and FIRE
lines
(Kukkonen et al., 2012, Geophysics)
Ilmo Kukkonen, Oct 17, 2012 6

7. Reflection seismic section FIRE-3 across the Outokumpu ore belt:
Faulting controlling ore belt structure
Ilmo Kukkonen, Oct 17, 2012 7
Kukkonen et al., 2012, Geophysics

8. Reflection seismics detects environments K: Keretti reflector
for Outokumpu-type deposits H: Horsmanaho reflector
D: Deep hole reflector
OKU 1
Kukkonen et al., 2012, Geophysics
Ilmo Kukkonen, Oct 17, 2012 8

9. Outokumpu Belt:
Possible direct seismic
indicators of deposits
Bright spots: Amplitude envelope
Strong reflection amplitudes… of a migrated stack
… and associated wave diffractions
Unmigrated stack
Ilmo Kukkonen, Oct 17, 2012 9

10. Correlation of reflectors and drilling profile in
the Outokumpu Belt
Host rock environments
of Outokumpu type deposits
K: Keretti reflector
H: Horsmanaho reflector
Drilling profile Pr 200 Kukkonen et al., 2012,
Adapted from Kontinen et al. (2006) Geophysics
Ilmo Kukkonen, Oct 17, 2012 10

11. 3D modeling of the Outokumpu fault
OKU2
OKU1
OKU3
Outokumpu fault
Kukkonen et al., 2012, Geophysics
Ilmo Kukkonen, Oct 17, 2012 11

12. 3D models of reflectors in the Outokumpu belt
Kukkonen et al., 2012, Geophysics
Ilmo Kukkonen, Oct 17, 2012 12

13. Case history 2:
Hannukainen-Rautuvaara,
FeOx-Cu-Au deposits
Ilmo Kukkonen, Oct 17, 2012 13

14. Geological setting
KSZ = Kolari Shear Zone
Ilmo Kukkonen, Oct 17, 2012 14

15. HIRE survey in the
Hannukainen-Rautuvaara target:
72 km of high resolution 2D lines
• FeOx-Cu-Au deposits
• Total inferred iron ore resource 16 Mt
• Mining 1974-1992
• By Rautaruukki Oy and Outokumpu Oy
• Currently exploration and deposit development
by Northland Exploration Finland Oy
• Host rock pyroxene skarn and/or albitite
• Deposits at contact zones between monzonite
intrusions of the Haparanda suite in W and the
Central Lapland Greenstone Belt in E
Ilmo Kukkonen, Oct 17, 2012 15

16. Hannukainen: FeOx-Cu-Au deposit
3D-visualization and modeling of reflectors
ÄSZ = Äkäsjoki Shear Zone
ÄTP = Äkäsjoki Thrust Plane
Rautuvaara
Hannukainen
Ilmo Kukkonen, Oct 17, 2012 16

17. Hannukainen: FeOx-Cu-Au deposit
Drilling data and reflectors
Drilling profile from Hiltunen 1982
Ilmo Kukkonen, Oct 17, 2012 17

18. Hannukainen: FeOx-Cu-Au deposit
Drilling data and reflector
Ilmo Kukkonen, Oct 17, 2012 18

19. Hannukainen: FeOx-Cu-Au deposit
Previously mined skarn /amphibolite layer
with semimassive magnetite Hannukainen
open pit
Depth (m)
Unknown
skarn/amphibolite
layers?
Ilmo Kukkonen, Oct 17, 2012 19

20. Conclusions
Reflection seismic surveys in previously mined and extensively
explored areas: Implications for mineral potential
• Previously unknown structures were revealed in all fifteen HIRE targets
•The structural database of the investigated deposit areas has considerably
expanded.
• Previously unknown potential host rocks of deposits were discovered in several
targets
• HIRE results have considerably increased the level of detailed knowledge at
previously unexplored depths
• Ore potential of the study areas may be higher than earlier anticipated
• The results encourage the continued application of seismic reflection surveys in
mineral exploration
Ilmo Kukkonen, Oct 17, 2012 20

21. Thank you for your attention!
Vniigeofizika vibrators at work in Vihanti 2007
Ilmo Kukkonen, Oct 17, 2012 21