All
I think IP is like geochem any anomaly above background should be looked at.
I can show you many case where the background is 5 to 6 ms and anything
above that is worth lookign at especially in the Moly end of the systems.
In matter of fact in some sediments I have seen background so low that
it was basically noise and 5 ms or mv/v whatever you like to call them
was anomalous and drilling proved up sulphides (unfortunately not
economical)
the bigger issue is convincing people to survey a big enough area to get
a good handle on background
Anything above background is anomalous although i agree with Kim i have
seen many cases where the highs are not the important anomalies but the
mid or lower end of the anomalous are the important targets. The actual
numbers are very meaningless.
In EM it is the same thing some real high conductivity conductors can be
a bust and some low conductivity conductors can be winners.
Syd
*Syd (Sipke) Visser, P.Geo.*
President, Snr. Geophysicist/Geologist
Tel: 1 (604) 582-1100
Cell: 1 (604) 813-1440
[email protected]
www.sjgeophysics.com <http://www.sjgeophysics.com>
<http://www.sjgeophysics.com>
On 2021-01-25 4:00 a.m., [email protected] wrote:
Today's Topics:
1. Re: Question for porphyry explorers ([email protected])
2. Re: Question for porphyry explorers ([email protected])
----------------------------------------------------------------------
Message: 1
Date: Mon, 25 Jan 2021 12:23:38 +0800
From: <[email protected]>
To: <[email protected]>
Subject: Re: [SEGMIN] Question for porphyry explorers
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"
I agree with Clark?s comments. About 14mV/V is my ?sulphide threshold? under
ideal circumstances.
Cheers
Barry
From: SEGMIN <[email protected]> On Behalf Of Clark Jorgensen
via SEGMIN
Sent: Sunday, 24 January 2021 1:20 PM
To: S E Geoscience and Exploration via SEGMIN <[email protected]>
Cc: Clark Jorgensen <[email protected]>
Subject: Re: [SEGMIN] Question for porphyry explorers
Sergio,
I usually get really excited if I see something that is greater than 15 mV/V
over background. That is just based upon looking up several papers where there
were good IP surveys that later became mines. But that is assuming you are
using the standard Newmont window (0.45 - 1.1 seconds) for a 2 second pulse.
Some contractors will deliberately choose earlier time windows so they get
bigger anomalies.
But of course, like Kim points out, the biggest response is from the outer halo
caused by the propylitic zone, so the main mineralized zone will most likely
have a weaker response.
Clark
On 1/23/21 1:49 PM, S E Geoscience and Exploration via SEGMIN wrote:
Dear all,
Question for all those porphyry explorers: What chargeability value would you
consider to be already anomalous for primary mineralization?
Of course this value does not only depend on Sulphide-%, but also on its type
of occurrence.
Thank you in advance for the discussion,
Regards
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