Junior
and Major Miners Show Ground Magnetics
is "One of a Diamond Finder's Best Friends"
One of the hottest targets
in mineral exploration is diamonds. Diamond exploration continues
to be well funded with many of the majors (Ashton, BHP-Billiton
and De Beers) at the leading edge of both financing and exploration
worldwide. In addition, many junior exploration groups are also
seeing opportunities for discoveries -- realizing the benefits
of flow-through financing and growing exploration excitement
in many jurisdictions.
Considerable
excitement these days is coming from juniors such as
Canabrava
Diamond Corporation. Canabrava's exploration
program focuses on Canada and Brazil and is paying off most
recently at Hadley Bay.
In
a joint announcement
Diamonds
North Resources Ltd. (the Hadley Bay operator
and 100% owner of the Blue Ice project) and Canabrava reported
that macrodiamonds were recovered from each of the first three
kimberlite samples processed from the King Eider pipe.
King Eider Discovery
The
King Eider kimberlite pipe was originally located using airborne
geophysics. A recent detailed ground geophysical survey, carried
out prior to drilling, has shown that King Eider is a large
complex kimberlite -- which includes the Jaeger, Turnstone,
Sanderling and Pintail kimberlites.
Click
here for larger image.
The
magnetic anomaly measures 200 by 300 metres. The detailed geophysical
survey, core logging and diamond analysis indicate that King
Eider is composed of multiple diamondiferous kimberlite phases.
Effectiveness
of Ground Magnetics
The
success of magnetics in diamond exploration stems from the ability
to quickly define the often circular and characteristic magnetic
anomalies related to kimberlite occurrences. In addition, magnetics
is often effective in delineating complex geologic structures,
as well as kimberlite dykes or other related features.
As
noted by Canabrava company president, George Read, "We
use airborne magnetics with helicopter surveys as well. In spite
of doing these surveys, we still have to get on the ground for
confirmation. There are always challenges in exactly positioning
anomalies and ground work is essential. I'm all for using ground
magnetics ... it's the best way to locate targets for drilling."
Sample
Data from Namib Desert, Namibia
The
following example shows data acquired with GEM's GSM-19 magnetometer
in the Namib Desert by another group active in exploration for
diamonds. Here, we see a sharply defined anomaly with multiple
components that may represent phases or multiple pipes. In addition,
we see evidence of cross-cutting structures that post-date the
kimberlite intrusions.
Model
computed courtesy of Encom Technology.
Evolutions
in Ground Geophysical Surveying
Ground
magnetic methods are also evolving to make the survey process
more efficient. The addition of
integrated
GPS systems for ground-based positioning speeds
up surveys. One source at a major mining group indicated that
they are already looking at new strategies with their ground
systems. Their approach is to send in survey teams to rapidly
map 25 to 50 targets on the ground, quickly interpret the results
and then return to the 7 to 10 hottest prospects.
Image
courtesy of Diamonds North Resources Ltd.
Published originally in the
Northern
Miner
September 30 - October 6 on front page article,
"Victoria Island diamond play gathers steam."
Evolutions
in survey procedures are made possible through GPS that enables
both geologists and geophysicists to run advanced magnetic instrumentation
with ease, and position / re-locate themselves on the ground
during follow-up. The result is that geologists can more effectively
identify drill locations and increase the potential for drilling
success.
Over
the past 22 years, GEM has become the standard in mineral exploration
ground magnetics based on evolutions, such as the Overhauser
GSM-19 magnetometer, and now, GPS. It's great to be part of
the success of junior exploration groups as well as the world's
majors who are augmenting their exploration programs with GEM
- "One of a Diamond Finder's Best Friends".
Note:
GSM-19 systems for the Hadley Bay project were rented
through
Terraplus
Inc., GEM's exclusive distributor for Canada.
