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getting a RAB rig, they don’t actually do RAB anymore. Part of
the reason for that is, as we’ve been saying, all the outcropping
deposits have been found.
“A lot of the easy RAB country has been drilled, that’s part of the
reason why they don’t do any RAB anymore, so you’ve got to
go to aircore and areas where there’s a bit thicker cover. I think
for some you will have to start looking deeper and deeper, but
there’s also still a few areas where the prospectors won’t have
found anything because of a couple of metres of sand.”
While discoveries such as Havieron have been made at significant
depths of about 400m below the surface, Osborne believes there
are still many more deposits to be found under shallow cover.
Phil Tornatora (De Grey), Justin Osborne (Matador/Hamelin)
and Philippa Sivwright (Newmont) “Most of the discoveries that we’ve seen in the last couple days
haven’t been really, really deep, they’ve just been under shallow
cover,” he said “If you want to find something quickly, that’s the
Justin Osborne is credited with making one of Australia’s greatest
space I’d be looking at before I get into somewhere really deep.
gold discoveries in recent memory, Gruyere, during his time with
“There’s plenty of places through the Tanami which have only
Gold Road Resources Ltd. Now a non-executive director with
5m or 15-20m of cover, but they have been either partially or
emerging explorers Matador Mining Ltd and Hamelin Gold Ltd,
ineffectively explored in the past because of cover. I think we’re
he believes the origin of this latest batch of new gold finds dates
getting much better at seeing through that. The processing of
back to the decision by most of the gold majors to cut off the tap
geophysics is helping dramatically with that.”
for greenfields exploration at the turn of the last decade.
Looking under cover for giant deposits
“Every single major gold mining company
is not something Mako Gold Ltd general
cut their teams right back and greenfields
manager exploration Ann Ledwidge is
exploration budgets, from 2010 to 2015,
having to consider for her company’s
dropped from around 40% to about 20%
efforts in Cote d’Ivoire just yet, but she
of global gold exploration [expenditure],” he
acknowledged that her approach to finding
said.
gold has changed over more than a
“All of those geologists from all those
decade focused on West Africa.
major companies then started going into
“I’m not envious [of the Australian explorers]
the juniors, so all of a sudden you had
because those deeper holes are expensive
this massive influx of talent going into the
so I think, in some ways, juniors have an
juniors, and even though there wasn’t a lot
easier time of it in West Africa,” she said.
of money for them, they had a lot of time to Jamie Rogers
do the work. “But I do see some analogies with having
to use better techniques in order to find things because when I
“During that time, some discoveries were made and we started
first went to West Africa 12 years ago, all our targeting was based
seeing money coming back. The nuggets were certainly the
on the artisanal showings. The big pit they were digging was your
first driver but then we actually started seeing legitimate money
geochem anomaly, they were doing the prospecting for us.
coming back into the sector, especially in Australia. Since then,
we’ve seen a plethora of fantastic discoveries.” “Now it’s not so easy. In the last decade, a lot of those artisanal
showings have been pegged and in Cote d’Ivoire, especially,
De Grey’s discovery of Hemi in the early months of 2020 was
they frown upon illegal miners so we’re having to use better
widely considered to be an unexpected find given previous
techniques, albeit on the surface. I definitely see a parallel with
explorers had passed over that area of the West Pilbara in
what’s happening in Australia, it’s just that the depth of the deposit
preceding years without a hint such a major deposit could be
you’re targeting is a bit different.”
lurking under the cover.
During the closing panel discussion, De Grey exploration
manager Phil Tornatora gave an insight into how the team came
to find Hemi and why he is confident more discoveries of this type
can be made.
“At Hemi, we trialed ultra-fine fraction soils over the top of it and
got absolutely no response, but there’s some areas where the
cover is a bit shallower than that and you do get a response,” he
explained.
“When I was a young geo, you sort of planned and logged
hundreds of thousands of metres of RAB drilling – and it’s
interesting now that when you talk to drilling companies about
Ann Ledwidge
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