TIDMKAV
RNS Number : 8161C
Kavango Resources PLC
13 February 2020
PRESS RELEASE
13 February 2020
KAVANGO RESOURCES PLC
("Kavango" or "the Company")
RESULTS OF DRILLING UNDERTAKEN ON THE KSZ BOTSWANA
Kavango Resources plc (LSE: KAV), the exploration group listed
on the Standard Listing Segment of the main board of the London
Stock Exchange and targeting the discovery of world-class base
metal deposits in Botswana, is pleased to announce the results of
the recent drilling programme on the Company's Kalahari Suture Zone
("KSZ") Project.
HIGHLIGHTS
-- The drilling has provided valuable geological information to
management to assist in the understanding of the potential of the
KSZ to host large Cu-Ni mineral deposits.
-- The assays from the core show elevated copper and nickel
values against what might be expected in a non-mineralised
gabbro.
-- Three gabbro sills were intersected and analysed during the
programme. These were from holes:
RIT50DH1 - at 58m depth, for 14m - average Cu 134ppm, Ni
205ppm
RIT50DH2 - at 58m depth, for 13m - average Cu 132ppm, Ni
226ppm
RIT08DH2 - at 121m depth, for 16m - average Cu 163ppm, Ni
181ppm.
-- Peak values were: 415ppm Ni, 189ppm Cu.
-- Discussions were held with several major mining companies at
the recent Mining Indaba Conference in Cape Town; interest was
shown in the size and potential of the KSZ to host mineral
deposits; a data room is currently being set up.
COMMENT AND INTERPRETATION
-- Kavango's exploration effort is currently directed towards
confirming that the conditions necessary for the formation of metal
sulphide orebodies existed during the emplacement of gabbroic
intrusives associated with a major volcanic episode during the late
Karoo geological era (180 Ma).
-- The 1,100m drilling programme, undertaken in November 2019,
confirmed the following parameters:
o The gabbro sills contain "primary" sulphides, which suggests
that the molten magma was in a condition of "sulphur saturation" at
the time of emplacement.
o The sills appear to favour emplacement within the coal and
shaley-coal bearing sediments of the Ecca (geological) formations.
Thus a source of additional sulphur would have been available to
encourage the development of metal sulphides within the cooling
magma.
o The existence of multiple (and relatively thin) gabbro sills
and dykes lying above a large gabbroic magma chamber, suggests the
development of a complex "plumbing system" feeding volcanic vents
on the ancient (paleo-) surface.
o Drill core logging confirms that these relatively thin
gabbroic bodies are associated with extensive heat alteration halos
(several metres) into the host rocks, which suggests that molten
magma was flowing through these "conduits" over prolonged periods.
This would allow for the accumulation of (heavy) metal sulphides in
physical traps during magma flow.
-- The assays from the core show slightly elevated copper and
nickel values against what would be expected in a non-mineralised
gabbro. This probably reflects the enrichment of these metals in
the fine disseminated sulphides seen in the thin sections (taken
from the core). However, these metals would have been leached out
of the crystalising silicate minerals by sulphur and probably
deposited elsewhere thus reducing the overall metal value in the
core. Polished thin sections and the whole rock geochemistry needs
to be undertaken to confirm this.
-- What was not confirmed was the ability of Kavango's CSAMT
geophysical system to identify massive sulphide bodies associated
with the gabbro sills. This is almost certainly due to the presence
of ground water contaminated with salt in and around the gabbroic
intrusions.
o Salty water absorbs electrical current and acts as an EM
conductor, which would tend to mask massive sulphide
minerlisation.
o Geophysical consultants have now advised Kavango that the use
of down-hole EM surveying and/or the use of much more powerful
transmitters from surface should be employed to discriminate
between the mildly conductive salty water and the much more
conductive massive sulphide mineralization.
FOLLOW UP
-- The Company is now in discussion with our geophysical
consultants to develop a geophysical method, either down-hole or
from surface that will discriminate between conductors caused by
saline groundwater and massive sulphide mineralization. Such
systems are available and need to be tested on the KSZ.
-- Down-hole EM surveys have the potential to search 300m from
the probe when placed in existing boreholes.
-- Additional tasks include:
o Generate computerized 3-D models of the geology of the KSZ and
combine this with the data obtained from the airborne EM
surveys.
o Complete polished thin sections to aid identification of metal
sulphide species.
o Commission a full analysis and report on the whole rock
geochemistry of the drill core by a recognised authority on
magmatic sulphide deposits.
Michael Foster, Chief Executive Officer of Kavango Resources,
commented:
"There is now a large body of evidence suggesting that the
accumulation of nickel and copper bearing metal sulphides occurred
within the high level gabbroic intrusions of the KSZ. The 3-D
modelling of the geological information obtained from the drilling,
together with all the geophysical surveys that have been completed,
is providing Kavango with much valuable information concerning the
genesis of the intrusives, the mechanisms of magma transport and
the chemistry of the magma itself. The next stage is to identify
and assess the value of these metal sulphide accumulations."
For further information please contact:
Kavango Resources plc +44 20 3651 5705
Michael Foster
mfoster@kavangoresources.com
SI Capital Limited (Joint Broker) +44 1483 413500
Nick Emerson
Turner Pope Investments (Joint Broker) +44 20 3657 0050
Andy Thacker and Zoe Alexander
Glossary of Terms
-- CSAMT: Kavango uses a ground based geophysical technique
known as Controlled Source Audio frequency Magneto Tellurics
(CSAMT) to identify the exact location of the conductors identified
in the airborne electromagnetic (AEM) survey. The shape,
orientation and depth of the conductors will determine if the
conductor should be drilled.
-- 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 deposit: The accumulation of metal
sulphides and their deposition within the intrusive is largely
dependent on the volume of magma that passes through the conduit.
The formation of a magmatic sulphide deposit requires the
precipitation of small amounts of metal sulphide from large amounts
of magma (lava) over a considerable time period
-- 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 sills: Relatively thin, planar bodies of solidified
gabbroic magma that intruded into layers of sedimentary rock whilst
still molten.
-- High level sills: Are sills that are emplaced in the upper
levels of the earth's crust, close to the surface.
-- 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.
-- 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.
-- Magma conduits: Beneath a volcano or multiple volcanic vents
and fissures there will exist a complex "plumbing system" of
(vertical) dykes and (horizontal) sills transporting magma (lava)
to the surface. In some cases these "conduits" can remain active
for hundreds of years accumulating metal sulphides in traps or
along the floor. These accumulations solidify to become massive
sulphide deposits
-- Electromagnetic (EM) surveys: are used to detect a wide
variety of mineral deposits, especially base metal sulphides (such
as copper and nickel), via detection of conductivity anomalies
which can be generated around sulphide bodies in the subsurface. On
a regional scale they are carried out via airborne methods, at
ground level for detailed follow-up work, or down a drill hole to
identify a body of mineralization under the conductive layers
above.
-- Downhole EM surveying: Downhole EM will be able to detect any
massive sulphide which the drill hole may have missed (off hole) as
well as beyond the extent of the drill hole. Since the receiver of
the downhole EM unit will be much closer to the source, it will be
able to detect bodies beyond the reach of surface and airborne
methods with less interference from Kalahari and Karoo sediments.
Radius of search is typically 300m.
****************************ENDS**************************************
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END
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