TIDMKAV
RNS Number : 9762C
Kavango Resources PLC
23 October 2020
PRESS RELEASE
23 October 2020
KAVANGO RESOURCES PLC
("Kavango" or "the Company")
Strong evidence of metal sulphide accumulations in the KSZ
Kavango Resources plc (LSE:KAV), the exploration company
targeting the discovery of world-class mineral deposits in
Botswana, is pleased to report further strong evidence that the
Kalahari Suture Zone (the "KSZ") may host one or more
"Norilsk-style" Copper-Nickel-Platinum Group Metal ("Cu-Ni-PGM")
deposits.
Dr David Holwell, of D&D Geoconsultants, has completed a
significant update to the Mineral Systems Review (first published
on 29 April 2020) (the "Review"). Dr Holwell is Associate Professor
of Geology at the University of Leicester and is a leading
authority on the development of Cu-Ni-PGM sulphide deposits
associated with magmatic plumbing systems.
Dr Holwell conducted a mineralogical study and laboratory
analysis of rock samples (the "Rock Samples") taken from the
Company's November 2019 drill campaign on the Hukuntsi section of
the KSZ and the Canadian sponsored Kalahari Drilling Programme
(1983). The Review makes several key conclusions.
Specifically, the occurrence of "primary magmatic sulphides" in
the thick "gabbroic sills" (>50m thick) of the KSZ (announced on
8 September 2020), combined with strong evidence of "sulphur
saturation" and the presence of "cumulate rocks", suggests that
"metal sulphides" may have accumulated in trap zones in sufficient
quantities to form mineable mineral deposits.
This is an extremely important step forward in advancing
Kavango's understanding of the KSZ.
There is now compelling evidence that the KSZ experienced
similar geological conditions as those that led to the formation of
giant Cu-Ni-PGM massive sulphide deposits at Norilsk (Siberia),
Voisey's Bay (Canada), Raglan (Canada), Jinchuan (China) and the
Thomson Nickel Belt (Canada).
A full description and glossary of terms is provided below.
The Company has also produced a short video, which shows how
magmatic sulphides might have accumulated in trap zones in the KSZ
to form massive sulphide deposits:
https://twitter.com/KavangoRes/status/1316004057895645186?s=20
Highlights
v In the Review Dr Holwell has concluded:
- There is now strong evidence that sulphur rich country rock
was incorporated into the mafic magma as it intruded into Karoo
sediments below the surface (as at Norilsk)
- This almost certainly led to the development of "sulphur
saturation" making the segregation of metal sulphides into a heavy
immiscible sulphide liquid more likely
- This does not seem to have occurred in the thinner sills
(<20m thick) where cooling and crystallisation took place
quickly.
- In the thicker sills (>50m thick), slow cooling of the
magma encouraged the formation of "cumulate textures" (large
silicate crystals in a fine-grained matrix)
- The Rock Samples from the thicker sills show clear evidence of
the development of primary magmatic sulphides in gabbroic cumulate
rocks
- As the sills cooled, the heavy metal sulphides would have sunk
through the cumulate rocks to accumulate in trap zones to form
massive sulphides.
- The primary metal sulphides include pyrrhotite (FeS), pyrite
(FeS(2) ) and chalcopyrite (CuFeS(2) ).
- Iron and copper sulphides appear to be in equal proportions.
- The presence of magmatic sulphides in the upper levels of the
thicker sills strongly indicates that the accumulation of massive
sulphides may have occurred in trap zones or at greater depths.
v Dr Holwell will now oversee the use of an electron-microprobe
to test for the depletion of Nickel in the Rock Samples
v In parallel, Kavango will apply the conclusions of Dr
Holwell's updated Review to the Company's 3D Geological Model of
the KSZ (the "Model), announced on 8 September 2020
- The goal will be to identify high-priority targets ("trap
zones") for further field exploration and drilling
Michael Foster, Chief Executive Officer of Kavango Resources,
commented:
"Dr Holwell's latest Review provides further strong evidence
that Kavango is on target for a major base metal discovery.
We are getting extremely close to validating our entire
exploration hypothesis for the Kalahari Suture Zone.
We will soon confirm our highest priority targets for the next
phase of field exploration and will aim to begin the ground-based
EM surveys before the end of the year. This will lead to drill
target selection and a drilling programme in 2021.
My thanks and congratulations to all of Kavango's geologists,
geophysicists and field staff who have done such a fantastic job
over the last few months analysing and interpreting significant
volumes of exploration data."
The Updated Review
In his "Mineral Systems Review of the Kalahari Suture Zone
Project" (April 2020), Dr Howell outlined a number of important
attributes of magmatic Cu-Ni-PGM deposits that, if present, would
represent strong support for the development of magmatic sulphide
deposits.
There is now strong evidence that sulphur rich country rock was
incorporated into the mafic magma as it intruded into Karoo
sediments below the surface (as at Norilsk).
This almost certainly led to the development of "sulphur
saturation" making the segregation of metal sulphides into a heavy
immiscible sulphide liquid more likely.
This does not seem to have occurred in the thinner sills
(<20m thick) where cooling and crystallisation took place
quickly. In the thicker sills (>50m thick), slow cooling of the
magma encouraged the formation of "cumulate textures" (large
silicate crystals in a fine-grained matrix).
The samples from the thicker sills of the KSZ show clear
evidence of magmatic sulphides in gabbroic cumulate rocks.
These sulphides include:
- Primary pyrite (FeS(2) )
- Primary Pyrrhotite (FeS)
- Primary Chalcopyrite (CuFeS(2) )
Iron and copper sulphides appear to be in equal proportions,
while Nickel sulphide (e.g. pentlandite) was not seen, possibly due
to its very fine grain size.
The presence of these primary sulphides confirms that a metal
sulphide liquid was able to segregate and that copper was one of
those metals.
The presence of disseminated magmatic sulphide in the upper
levels of the thicker sills strongly indicates that the
accumulation of massive sulphides may have occurred in trap zones
or at greater depths.
Now that Kavango has received Dr Holwell's updated Review we can
confirm the presence of the following geological characteristics in
the KSZ:
- Presence of Cumulate Rocks
- Sulphur rich xenoliths and interaction of country rocks with the magma
- Slow cooling textures
- Sulphide liquid segregation
Electron-microprobe of Rock Samples
As previously announced, Kavango has agreed with Dr Holwell to
support a research project in conjunction with a MSc student from
the University of Leicester entitled "A Comparison of the
Mineralogy and Geochemistry of the Mafic Intrusives of the Kalahari
Suture Zone (Botswana) and Norilsk/Talnakh (Siberia)".
Work has already started on this project, which will employ
advanced analytical techniques available at the University of
Leicester. This will include use of an electron-microprobe on drill
core samples from the KSZ provided by Kavango. The purpose of this
test will be to confirm Ni-depletion in olivine and pyroxenes. (If
these silicate minerals show depletion of Ni, it suggests that the
sulphur has "scavenged" the Ni from the melt preventing its
incorporation into the silicate lattices).
It is anticipated that this work will provide final confirmation
that the KSZ shares all the geological characteristics of other
major world-class magmatic sulphide Cu-Ni-PGM deposits.
The Company will provide a further update to the Mineral Systems
Review in due course.
Drill Target Identification
Using the 3D Geological Model constructed by the Company's
in-house geophysics team in collaboration with Mira Geoscience,
together with the updated conclusions of the Review, Kavango will
now work to confirm its initial high-priority targets for further
field exploration.
Specifically, the Company aims to use ground based, high power,
low frequency, long loop, EM surveys to identify the thickest parts
of the sills, where concentrations of magmatic sulphides may have
accumulated to form conductive bodies.
The identification of such metallic conductors will pave the way
towards drill target selection and a major drilling programme in
2021.
Further information in respect of the Company and its business
interests is provided on the Company's website at
www.kavangoresources.com and on Twitter at #KAV.
For further information please contact:
Kavango Resources plc
Michael Foster
mfoster@kavangoresources.com
SI Capital Limited (Broker)
+44 1483 413500
Nick Emerson
Note to Editors:
THE KALAHARI SUTURE ZONE
Kavango's 100% subsidiary in Botswana, Kavango Minerals (Pty)
Ltd, is the holder of 12 prospecting licences covering 8,324.7km(2)
of ground, including 10 licences over a significant portion of the
450km long KSZ magnetic anomaly in the southwest of the country
along which Kavango is exploring for Copper-Nickel-PGM rich
sulphide ore bodies. This large area, which is entirely covered by
Cretaceous and post-Cretaceous Kalahari Sediments, has not
previously been explored using modern techniques.
The area covered by Kavango's KSZ licences displays a geological
setting with distinct similarities to that hosting World Class
magmatic sulphide deposits such as those at Norilsk (Siberia) and
Voisey's Bay (Canada).
The Norilsk mining centre is about 2,800km northeast of Moscow
and accounts for 90% of Russia's nickel reserves, 55% of its copper
and virtually all of its PGMs. Kavango's licenses in the KSZ
display a geological setting with distinct geological similarities
to the magmatic sulphide deposits at Norilsk. Magma plumbing
systems are a key feature of these deposits.
KSZ DEFINITIONS
Cumulate rocks: A feature of some intrusive igneous rocks in
which the crystallisation of some minerals occured before others.
This produces a rock composed of large crystals (cumulus crystals)
enclosed within a fine grained (inter-cumulus) phase. The
unevenness in the rate of crystalisation can lead to layering of
mineral phases during cooling. In mafic (gabbros) or ultra mafic
magmas, the first minerals to crystallise are usually the heavier,
iron rich minerals which tend to sink to the bottom of the magma
chamber.
Gabbro/gabbroic: A coarse grained, medium to dark coloured rock,
formed from the intrusion of mantle derived molten magma into the
earth's crust. Gabbroic rocks (or "gabbros") are formed as the
molten magma crystallizes and cools.
Gabbroic sills: Relatively thin, planar, horizontal bodies of
solidified gabbroic magma that intruded into layers of sedimentary
rock whilst still molten.
Karoo: The Karoo System covers 1.5 million km(2) of the
semi-desert region of Southern Africa. Rocks in this system formed
180-310 million years ago.
Magma plumbing system: Magma plumbing systems are composed of
stacked horizontal sills connected to each other via vertical
dykes. A continuous flow of magma (containing "free" sulphur)
through a magma plumbing system may have allowed the accumulation
of metal sulphides in certain trap sites within the sills. This is
because metal sulphides are heavy and tend to sink to the bottom of
magma. Over time, accumulations of metal sulphide could have led to
the formation of economic deposits of Copper-Nickel-PGMs.
Massive sulphide: When a deposit consists almost entirely of
sulphides it is termed "massive". When it consists of grains or
crystals of sulphide in a matrix of silicate minerals, it is termed
"disseminated".
Magmatic sulphide: Primary sulphide minerals found in igneous
rocks and formed within a cooling and crystallising magma from
sulphur and metal ions in the melt. Deposits of sulphide mineral
concentrations in mafic and ultramafic rocks, derived from
immiscible sulphide liquids. To view a video of how metal/magmatic
sulphides form please visit -
https://twitter.com/KavangoRes/status/1316004057895645186?s=20
Olivine: an olive-green, grey-green, or brown mineral occurring
widely in basalt, peridotite, and other basic igneous rocks. It is
a silicate containing varying proportions of nickel, copper, iron
and other elements. Depleted Cu-Ni-PGM readings in olivines are an
encouraging exploration vector, when search for major Cu-Ni-PGM
deposits.
Primary sulphides: Are sulphide complexes (or crystals) that
form as the magma cools and are composed of elements that are
present at the time of initial crystallization. Secondary sulphides
may form after the magma has solidified either by the introduction
of new elements into the rock or by re-mobilising elements already
present through changes in pressure, heat etc.
Pyrite: A shiny yellow metallic-looking mineral composed of iron
sulphide (FeS2).
Sulphide mineralisation : If there is sufficient sulphur in the
molten magma, it will tend to combine with metals (Cu, Zn, Ni, Co,
Pb, PGEs etc.) to form metal sulphide complexes, which may coalesce
to form massive sulphide deposits. If the melt is sulphide poor,
the metals will be taken up into the silicate minerals that form as
the magma cools and will not usually form economic deposits.
Xenolith: A xenolith is a piece of rock trapped in another type
of rock. Usually, a xenolith is a piece of country rock
incorporated into molten magma whilst it is intruding the earth's
crust.
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