Seismic method - Geophysics for the Mineral Exploration Geoscientist - page 402

S N

a)

400

300 350 450 500 SP

0.0

0

0.1

500

0.2

0.3

1000

0.4

1500

0.5

0.6

2000

Two-way
time (s)

Approximate
depth (m)

0 1000

Metres

b)

300 350 400 450

500 SP

0.0

0

0.1

DR

Wabassee \group

KT

500

0.2

0.3

Watson
Lake Group

1000

Gabbro sills

BA

0.4

1500

0.5

Bell River
Complex

0.6

2000

Two-way
time (s)

Approximate
depth (m)

Figure 6.48 Migrated zero-offset seismic re ection section across part of the southwestern limb of the Galinée Anticline. (a) Uninterpreted data,

and (b) major stratigraphic markers and faults (red) interpreted from the data. BA - Bell Allard VMS deposit, DR - Dumagami Rhyolite,

KT - Key Tuffite. Redrawn, with permission, from Calvert and Li ( 1999 ) .

6.8.1 In-seam surveys

Fig. 6.1 ) . In-seam surveys, as the name suggests, are the
domain of the coal industry. Drillhole-to-drillhole (down-
hole) tomographic surveys have been successfully applied
to bodies of massive sulphide mineralisation.

Coal seams have seismic properties that are usually very
different from the host strata ( Fig. 6.35 ) . Coal has lower
density and lower seismic velocity than most rocks, which