Lessons learnt from three massive sulphides test sites

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

Geological provinces in Québec Abitibi greenstone Belt

600 m 700 n. T/s (off time) Py Zn Cu semimassive sulphide 800 m Iso New Insco

Gallen deposit

p. H = 2. 3 Aldermac

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?

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

What we have learnt?

30 Hz L 301 90 Hz L 501 N Iso copper rich zone 30 Hz 90 Hz

MEGATEM flights over Iso deposit at different altitudes (line 100501) 35000 f. T 35000 100000 300000 461 m 371 m 274 m 187 m 122 m Bx 35000 f. T 461 m 35000 371 m 35000 100000 274 m 187 m 300000 122 m 250 m 500 m 750 m 1000 m Bz

channel 6 channel 20 350 450 channel 6 overburden conductance = 1. 2 S channel 20

In the down-dip direction 700 n. T/s Bx 0 By Bz By 700 n. T/s 0 Basalt Diorite Rhyolite Bz 250 Basalt Diorite Massive sulphide Rhyolite 500 Massive sulphide 500 Dacite (m) 700 n. T/s 0 0 750 Bx 0 0 700 n. T/s 250 700 n. T/s 0 In the up-dip direction Dacite Basalt Andesite 750 (m) Basalt Andesite

X up - dip down - dip Z W 30 o 60 o Plate model: 600 m in width, 800 m in deep extension at 50 m depth 30 o E

a b c d X old X new Z old Z new

3 D modeling tools for EM data interpretation (EMIT_Au) • (U_Toronto) Maxwell • Plate Thin sheet • Leroi. Air (Pet. Ros_Ei. Kon) • Emigma • Macro. Air (CSIRO_Au) (GSS_Au) Polyhedron Prism • Arjuna. Air • Em. Q • Loki. Air 2. 5 D Sphere 3 D

30 S 20 S 55 S 40 S

Gallen deposit

Gallen deposit

Aldermac deposit

Line 401 10000 p. T/s 30 Hz Aldermac deposit d. Bx/dt Line 501 30 Hz d. Bx/dt 0 measured 10000 p. T/s d. Bz/dt 0 measured 10000 p. T/s d. Bx/dt 0 Thick prism 10000 p. T/s 0 d. Bz/dt 0 Thick prism d. Bz/dt Thick prism 3 km 0 3 km

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