TIDMCOBR
RNS Number : 1048Y
Cobra Resources PLC
07 May 2019
THIS ANNOUNCEMENT CONTAINS INSIDE INFORMATION FOR THE PURPOSES
OF ARTICLE 7 OF EU REGULATION 596/2014. UPON THE PUBLICATION OF
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7 May 2019
Cobra Resources plc
("Cobra" or the "Company")
Wudinna Gold Project Resource Update
Cobra (LSE:COBR), a company formed to explore, develop and mine
precious and base metal projects, today announces that it has
received an updated Mineral Resource estimate for the Wudinna Gold
Project, located in the Eyre Peninsula of South Australia
approximately 25 km north of the township of Wudinna (the "Wudinna
Gold Project").
The Wudinna Gold Project is 100% owned by Andromeda Metals
Limited ("Andromeda"), a company listed on the Australian
Securities Exchange. On 31 October 2017, Andromeda entered into a
binding agreement with Lady Alice Mines Pty Ltd ("Lady Alice
Mines"), pursuant to which Lady Alice Mines can earn an up-to 75%
interest in the Wudinna Gold Project (the "Wudinna Agreement"). On
6 March 2019, the Company entered into an agreement to acquire the
entire issued share capital of Lady Alice Mines and 100% of the
units in the Lady Alice Trust (the "Lady Alice Acquisition").
Further details of the Wudinna Agreement and the Lady Alice
Acquisition can be found in the Company's announcement entitled
"Proposed Acquisition of Lady Alice Mines" released via regulatory
news service on 7 March 2019 (the "Acquisition Announcement").
Defined terms used but not defined herein shall have the same
meanings given to such terms in the Acquisition Announcement.
Following the geological reinterpretation of the Barns, White
Tank and Baggy Green deposits by Lady Alice Mines in 2018, Cobra
instructed Optiro Pty Ltd ("Optiro"), a well-renowned mining
services company based in Perth, Western Australia, to re-estimate
the gold resources for the Wudinna Gold Project in accordance with
the Joint Ore Reserves Committee 2012 Guidelines.
Key Highlights:
-- The updated Mineral Resource has increased to 4.43 million
tonnes at 1.5 g/t gold for 211,000 ounces of gold. The previous
resource estimate was 3.85 million tonnes at 1.6 g/t gold for
200,300 ounces.
-- This update represents an increase of 5% in contained gold and 15% in resource tonnes.
-- This resource includes 4.02 million tonnes at 1.5 g/t gold
for 193,000 ounces of Inferred resource and 0.41 million tonnes at
1.4g/t gold for 18,000 ounces of Indicated resource.
-- This represents an increase of 0.59 million tonnes or 10,700
ounces of gold when compared to the previous Mineral Resources
announced by Andromeda on the 23(rd) January 2017 (refer:
http://www.andromet.com.au/images/uploads/reports/20170123_BG_WT_Resource_FINAL.pdf).
-- The Barns, White Tank and Baggy Green deposits are located
within 6 km of each other and are shallow and potentially
open-pitable.
-- Each of the deposits remain open and step-out drilling can
potentially add further resources.
Craig Moulton, Managing Director of Cobra commented:
"I am delighted with the updated resource estimate for this key
project in Cobra's portfolio. The increase in the JORC Mineral
Resource based on this new interpretation, and without new drilling
data, confirms our belief that there is significant value to be
unlocked from this exciting project."
Detail:
The Mineral Resource estimate, as at March 2019, for the Barns,
White Tank and Baggy Green deposits is shown below in Table 1.1.
This has been classified and reported in accordance with the
guidelines of the Australasian Code for Reporting of Identified
Mineral Resources and Ore Reserves, 2012 (the "JORC Code"). The
Mineral Resources have been reported above a 0.5 g/t gold cut-off
grade to reflect current commodity prices and extraction by open
pit mining.
Table 1.1 Classification Tonnes Grade (g/t Gold ounces
Mineral (x1,000) gold)
Resource
estimates,
using alternative
interpretation
and reported
above a
cut-off
grade of
0.5 g/t
gold:Deposit
Barns Indicated 410 1.4 18,000
Inferred 1,710 1.5 86,000
------------------------------------- ---------- ----------- ------------
Total 2,210 1.5 104,000
------------------------------------- ---------- ----------- ------------
White Tank Inferred 280 1.4 13,000
---------------- ---------- ----------- ------------
Baggy Green Inferred 2,030 1.4 94,000
---------------- ---------- ----------- ------------
Total 4,430 1.5 211,000
---------- ----------- ------------
Gold mineralisation at the Wudinna Gold Project is associated
with a large hydrothermal alteration halo within granodiorite. At
Baggy Green, the host rocks are visibly altered and sheared in and
around the mineralised zone. Mineral Resources were previously
estimated by Mining Plus Pty Ltd ("Mining Plus") for Andromeda in
2016 for the Barns deposit and in 2017 for the White Tank and Baggy
Green deposits.
In 2018, Lady Alice Mines requested Optiro to investigate an
alternative orientation to the interpreted mineralisation at Barns,
White Tank and Baggy Green aligned with the strong regional
northwest/southeast orientation observed in:
-- calcrete gold geochemical data;
-- regional gravity and magnetic data; and
-- structural interpretation of drill core data.
Variography indicated that the maximum continuity for the
mineralisation at Barns is orientated along 305deg, which is
consistent with the regional orientation observed by Lady Alice
Mines. Lady Alice Mines requested Optiro to re-model the
mineralisation at Barns, White Tank and Baggy Green using this as
the dominant orientation for the mineralisation and to develop
alternative conceptual resource models.
In April 2019, Cobra requested Optiro to re-estimate the Barns,
White Tank and Baggy Green resources incorporating this alternative
interpretation and new variography.
A nominal cut-off grade of 0.3 g/t gold was used for
interpretation of the mineralisation at Barns, White Tank and Baggy
Green.
Interpreted mineralisation at Barns extends over and area of 400
mN by 250 mE and is up to 200m deep. Two lodes of flat-lying
supergene mineralisation and 12 lodes of shallow dipping, fresh
mineralisation have been interpreted. At White Tank, the
interpreted mineralisation extends for 250 mN by 150 mE and is up
to 120m deep. One lode of flat-lying mineralisation and two shallow
dipping lodes of mineralisation within fresh material have been
interpreted.
The Baggy Green resource has two areas of mineralisation: within
the south the interpreted mineralisation extends over an area of
200 mN by 400 mE and in the north it extends over an area of 150 mN
by 300 mE. One lode of flat-lying supergene mineralisation and 13
shallow dipping lodes of mineralisation have been interpreted
within the fresh material to a depth of 200m.
The resource models for the Barns and White Tank deposits were
constructed using a parent block size of 10 mE by 10 mN on 4m
benches; the parent blocks were allowed to sub-cell down to 2 mE by
2 mN by 0.5 mRL to more accurately represent the geometry and
volumes of the weathering horizons and mineralisation domains. For
Baggy Green, a parent block size of 20 mE by 20 mN by 5 m was used
and the parent blocks were allowed to sub-cell down to 4 mE by 4 mE
by 1 m RL.
Gold block grades were estimated using ordinary kriging
techniques, with search ellipses oriented within the plane of the
mineralisation. Hard boundary conditions were applied for grade
estimation into each of the mineralised domains (i.e. grade
estimation for each domain used only the data that is contained
within that domain).
A total of 255 bulk density determinations have been undertaken
at Barns on either historical or recent diamond drillholes and 185
bulk density determinations have been undertaken at Baggy Green on
recent diamond drillholes. Average values were calculated from the
complete dataset by Mining Plus using a combination of weathering
and mineralisation. Density values assigned to the mineralised
domains in the resource models range from 2.29 t/m(3) to 2.73
t/m(3) .
The mineralisation at Barns, White Tank and Baggy Green has been
classified as Indicated and Inferred in accordance with the
guidelines of the JORC Code. The Mineral Resources have been
classified on the basis of confidence in geological and grade
continuity and taking into account data quality (including sampling
methods), data density and confidence in the block grade
estimation, using the modelled grade continuity and conditional
bias measures (slope of the regression) as criteria.
Indicated Mineral Resources have been defined at Barns within
the supergene mineralisation in areas where drill spacing is
generally 20 mE by 50 mN or less. An Indicated classification was
applied to four of the fresh lodes where the drill spacing is
generally 20 mE by 50 mN or less and the resources are above 40
mRL. Inferred Mineral Resources have been defined in areas where an
extension of mineralisation is supported by the drilling. The total
Mineral Resources at White Tank and Baggy Green have been
classified as Inferred.
The likelihood of eventual economic extraction was considered in
terms of possible open pit mining and results from metallurgical
testwork. Metallurgical testwork from material at Barns and Baggy
Green indicated gold recoveries ranging from 94.3% to 99.3% and
averaging 97.7% across all samples from a combination of
conventional gravity and cyanide leaching.
Competent Person Statement - Resource Estimation:
The information in this release that relates to the Estimation
and Reporting of Mineral Resources has been compiled by Mrs
Christine Standing BSc Hons (Geology), MSc (Min Econs), MAusIMM,
MAIG. Mrs Standing is a full-time employee of Optiro and has acted
as an independent consultant on the Mineral Resource Estimates for
the Barns, Baggy Green and White Tank Deposits. Mrs Standing is a
Member of the Australian Institute of Geoscientists and the
Australian Institute of Mining and Metallurgy and has sufficient
experience with the style of mineralisation, deposit type under
consideration and to the activities undertaken to qualify as a
Competent Person as defined in the 2012 Edition of the JORC Code.
Mrs Standing consents to the inclusion in this report of the
contained technical information relating the Mineral Resource
estimations in the form and context in which it appears. The
detailed Mineral Resources estimation parameters per Table 1 of the
JORC Code are set out in Appendix One.
Cautionary Statement
Readers should use caution when reviewing the exploration and
historical production results presented and ensure that the
Modifying Factors described in the 2012 edition of the JORC Code
are considered before making an investment decision.
Additional details on this resource update can be found on
Cobra's web site: www.cobraresourcesplc.com
The person who arranged for the release of this announcement on
behalf of the Company was Craig Moulton, Managing Director of the
Company.
End
Enquiries:
Cobra Resources plc Rolf Gerritsen +44 (0)20 7129 1471
Nick Emerson
SI Capital Limited (Broker) Sam Lomanto +44 (0)14 8341 3500
------------------ ----------------------
Appendix One: JORC Code Table 1 Criteria
The table below summaries the assessment and reporting criteria
used for the Barns, White Tank and Baggy Green Mineral Resource
estimates and reflects the guidelines in Table 1 of The
Australasian Code for the Reporting of Exploration Results, Mineral
Resources and Ore Reserves (the JORC Code, 2012). Data included in
Sections 1 and 2 has been extracted from Adelaide Resources
Limited, 2016 and Andromeda Metals Limited, 2017.
Section 1 Sampling Techniques and Data
Criteria JORC Code explanation Commentary
Sampling
techniques * Nature and quality of sampling. * Aircore (AC), rotary air-blast (RAB), RC (reverse
circulation), rotary hammer (RH) and diamond drilling
has been used to obtain 6 m composite and 1 m samples
* Include reference to measures taken to ensure sample which have been pulverised to produce sub samples for
representivity and the appropriate calibration of any laboratory assay (nominal 50 g or 30 g charge for
measurement tools or systems used. gold fire assay with AAS finish).
* Data from AC and RAB holes have not been used for
resource estimation.
* Some samples have also been assayed for a suite of
other elements using multi-acid digest of small
weight charges finished with ICP-OES and ICP-MS).
* Some screen fire assays have been completed where
coarse gold was suspected to be present.
* RC and many of the RH, AC and RAB samples have been
riffle split if dry. Wet samples have been
sub-sampled using trowels.
* Diamond core has been sawn in half, with half core
submitted for assay.
------------------------------------------------------------ ----------------------------------------------------------------
Drilling
techniques * Drill type (e.g. core, reverse circulation, open-hole * Drill methods include AC, RH and RAB in
hammer, rotary air blast, auger, Bangka, sonic, etc) unconsolidated regolith and aircore hammer in hard
and details (e.g. core diameter, triple or standard rock. Some shallow RC holes have been drilled in
tube, depth of diamond tails, face-sampling bit or place of AC and RAB.
other type, whether core is oriented and if so, by
what method, etc).
* Hole diameter for AC was 90 mm. RC hole diameters
were generally 4.5 to 5.5 inch with face sampling
hammers employed.
* Diamond core was HQ/ NQ2 diameter.
* Data from AC and RAB holes have not been used for
resource estimation.
------------------------------------------------------------ ----------------------------------------------------------------
Drill sample
recovery * Method of recording and assessing core and chip * Qualitative assessment of sample recovery and
sample recoveries and results assessed. moisture content of all drill samples has been
recorded.
* Measures taken to maximise sample recovery and ensure
representative nature of the samples. * Sample cyclone cleaned at end of each hole and as
required to minimise down-hole and cross-hole
contamination.
* Whether a relationship exists between sample recovery
and grade and whether sample bias may have occurred
due to preferential loss/gain of fine/coarse * Core recovery has not been calculated in early
material. diamond holes. Core recovery has been recorded in the
2015 diamond drilling and was very high.
* No relationship is known to exist between sample
recovery and grade.
* Results of three twinned RC and diamond core hole
pairs indicates that RC samples may be under-sampling
gold, as the diamond core holes returned between 30%
and 70% higher grades for equivalent intervals.
------------------------------------------------------------ ----------------------------------------------------------------
Logging
* Whether core and chip samples have been geologically * All drillholes have been geologically logged by
and geotechnically logged to a level of detail to on-site geologist, with lithological, mineralogical,
support appropriate Mineral Resource estimation, weathering, alteration, mineralisation and veining
mining studies and metallurgical studies. information recorded. The drillholes have not been
geotechnically logged, except for basic BPM and RQD
on the three diamond drillholes completed in 2015.
* Whether logging is qualitative or quantitative in
nature. Core (or costean, channel, etc) photography.
* Geological logging is qualitative.
* The total length and percentage of the relevant
intersections logged. * Chip trays containing 2 m sub-samples from AC, RAB
and RC drillholes have been collected and
photographed at the completion of the drilling
programme.
* 100% of any reported intersections (and of all metres
drilled) have been geologically logged.
------------------------------------------------------------ ----------------------------------------------------------------
Sub-sampling
techniques * If non-core, whether riffled, tube sampled, rotary * Diamond core has been sawn in half to present a 1/2
and sample split, etc and whether sampled wet or dry. core assay sample. Duplicates have been 1/4 core
preparation sawn.
* For all sample types, the nature, quality and
appropriateness of the sample preparation technique. * Samples from AC, RAB and "bedrock" RC holes have been
collected initially as 6 m composites followed by 1 m
re-splits. Many of the 1 m re-splits have been
* Quality control procedures adopted for all collected by riffle splitting.
sub-sampling stages to maximise representivity of
samples.
* RC samples have been collected by riffle splitting if
dry, or by trowel if wet.
* Measures taken to ensure that the sampling is
representative of the in situ material collected,
including for instance results for field * Recent RC sampling has been split by cone splitter
duplicate/second-half sampling. (12.5% Split) and 1m samples through prospective
zones have been submitted to the laboratory.
* Whether sample sizes are appropriate to the grain
size of the material being sampled. * Laboratory sample preparation included drying,
crushing if 1/2 core, and pulverising of submitted
sample to target of P80 at 75 um.
* Pulverised samples have been routinely checked for
size after pulverising.
* Laboratory analytical charge size included 30 g and
50 g standard sizes which are considered adequate for
the material being assayed, although the presence of
coarse gold was suspected in some samples based on
variability in grade of multiply assayed samples.
------------------------------------------------------------ ----------------------------------------------------------------
Quality of
assay data * The nature, quality and appropriateness of the * Standard laboratory analyses completed for gold (fire
and assaying and laboratory procedures used and whether assay).
laboratory the technique is considered partial or total.
tests
* The laboratory analytical methods used are considered
* Nature of quality control procedures adopted (e.g. to be total.
standards, blanks, duplicates, external laboratory
checks) and whether acceptable levels of accuracy
(i.e. lack of bias) and precision have been * For laboratory samples the Company introduced QAQC
established. samples (standards and duplicates) at a ratio of one
QAQC sample for every 22 to 24 drill samples. The
laboratory additionally introduced QAQC samples
(blanks, standards, checks).
* Both the Company and laboratory QAQC samples indicate
acceptable levels of accuracy and precision have been
established.
------------------------------------------------------------ ----------------------------------------------------------------
Verification
of sampling * The verification of significant intersections by * The Company has submitted a substantial number of
and assaying either independent or alternative company personnel. significant intersection as well as QAQC Standard and
Blanks to a third Party "Umpire" laboratory.
* The use of twinned holes.
* Three RC holes at Barns have been twinned with
diamond holes. Results showed that grades were on
* Documentation of primary data, data entry procedures, average higher than the RC holes.
data verification, data storage (physical and
electronic) protocols.
* At Baggy Green there has been 1 RC hole "twinned"
with a diamond hole in 2015, Grades are comparable
* Discuss any adjustment to assay data. between holes.
* There have been no twinned holes completed at White
Tank.
* The Company has not had umpire assay checks completed
on any White Tank material but has verified the
laboratory competencies with umpire checks from other
nearby prospects (Barns and Baggy Green). The
competent person and another company geologist have
checked the results as well.
* Andromeda Metals uses a Maxwell's Datashed database
to store and validate its drilling data.
* No adjustments have been made to the laboratory assay
data.
------------------------------------------------------------ ----------------------------------------------------------------
Location of
data points * Accuracy and quality of surveys used to locate * Drillhole collars have normally been pegged using
drillholes (collar and down-hole surveys), trenches, DGPS with an accuracy of +/-0.5 m.
mine workings and other locations used in Mineral
Resource estimation.
* Downhole surveys have been completed for deeper RC
and diamond drillholes.
* Specification of the grid system used.
* The co-ordinate system used during the historic
* Quality and adequacy of topographic control. exploration programme was AMG84 Zone 53.
* Since this time the coordinates have been converted
into MGA94 Zone 53 datum.
* Collar RLs have been created from a high resolution
DTM, acquired from a geophysical survey.
------------------------------------------------------------ ----------------------------------------------------------------
Data spacing
and * Data spacing for reporting of Exploration Results. * Drill lines at Barns have been drilled mainly on a 50
distribution m section spacing with some sections having been
drilled 25 m apart. Drillhole spacings on section
* Whether the data spacing and distribution is vary but on average are in the order of 20 m apart.
sufficient to establish the degree of geological and
grade continuity appropriate for the Mineral Resource
and Ore Reserve estimation procedure(s) and * Drill lines at Baggy Green have been drilled mainly
classifications applied. on a 50 m section spacing. Drillhole spacing on
section vary but on average are in the order of 20 to
50 m apart.
* Whether sample compositing has been applied.
* Drill lines at White Tank have been drilled mainly on
a 50 m section spacing. Drillhole spacing on section
vary but on average are in the order of 10 to 50 m
apart.
* The assay data has been composited for resource
estimation purposes.
------------------------------------------------------------ ----------------------------------------------------------------
Orientation
of data in * Whether the orientation of sampling achieves unbiased * Drill lines oriented east-west at Barns and Baggy
relation to sampling of possible structures and the extent to Green.
geological which this is known, considering the deposit type.
structure
* Drill lines initially oriented east--west then
* If the relationship between the drilling orientation changed to northwest-southeast at White Tank.
and the orientation of key mineralised structures is
considered to have introduced a sampling bias, this
should be assessed and reported if material. * It remains unknown if internal mineralised structures
exist at different orientations to the overall strike
of mineralisation at Barns and Baggy Green.
* Evidence from a drill traverse with 10 m hole spacing
is that high grade shoots of gold are present in the
overall plane of mineralisation at White Tank.
------------------------------------------------------------ ----------------------------------------------------------------
Sample
security * The measures taken to ensure sample security. * Company staff collected or supervised the collection
of all laboratory samples.
* Samples submitted to the laboratory samples have been
transported by a local freight contractor.
* There exists no suspicion that the historic samples
have been tampered with at any stage.
------------------------------------------------------------ ----------------------------------------------------------------
Audits or
reviews * The results of any audits or reviews of sampling * There have been no external audits or reviews of the
techniques and data. sampling techniques and data.
------------------------------------------------------------ ----------------------------------------------------------------
Section 2 Reporting of Exploration Results
Criteria JORC Code explanation Commentary
Mineral
tenement and * Type, reference name/number, location and ownership * The Barns and White Tank deposits are within EL 5092
land tenure including agreements or material issues with third and is owned 100% by Peninsula Resources limited, a
status parties such as joint ventures, partnerships, wholly owned subsidiary of Andromeda Metals Limited.
overriding royalties, native title interests,
historical sites, wilderness or national park and
environmental settings. * The Baggy Green deposit is within EL5120, owned 100%
by Peninsula Resources limited, a wholly owned
subsidiary of Andromeda Metals Limited.
* The security of the tenure held at the time of
reporting along with any known impediments to
obtaining a licence to operate in the area. * Newcrest Mining Limited retains a 1.5% NSR royalty
over future mineral production from both licences.
* The Barns and White Tank deposits are on Perpetual
Leasehold land used for cereal cropping.
* Native Title is extinguished on Perpetual Leasehold
land (Barns and White Tank).
* A Native Title Agreement has been negotiated with the
NT Claimant and has been registered with the SA
Government.
* Aboriginal heritage surveys have been completed over
the Barns and White Tank deposit areas with no sites
located in the immediate vicinity of the deposits.
* A Compensation Agreement is in place with the
relevant agricultural landowner.
* Baggy Green is located within Pinkawillinnie
Conservation Park. Native Title Agreement has been
negotiated with the NT Claimant and has been
registered with the SA Government.
* Aboriginal heritage surveys have been completed over
the Baggy Green project area, with no sites located
in the immediate vicinity.
* A Native Title Agreement is in place with the
relevant Native Title party.
--------------------------------------------------------------- -------------------------------------------------------------
Exploration
done by other * Acknowledgment and appraisal of exploration by other * On-ground exploration completed prior to Andromeda
parties parties. Metals' work was limited to 400 m spaced soil
geochemistry completed by Newcrest Mining Limited
over the Barns prospect.
* Other than the flying of regional airborne geophysics
and coarse spaced ground gravity, there has been no
recorded exploration in the vicinity of the Baggy
Green deposit prior to Andromeda Metals' work.
--------------------------------------------------------------- -------------------------------------------------------------
Geology
* Deposit type, geological setting and style of * The deposits are considered to be either a lode gold
mineralisation. or intrusion related mineralisation related to the
1,590 Ma Hiltaba/GRV tectonothermal event.
* Gold mineralisation is associated with significant
alteration of host rocks.
--------------------------------------------------------------- -------------------------------------------------------------
Drillhole
Information * A summary of all information material to the * Exploration results are not being reported for the
understanding of the exploration results including a Mineral Resources areas.
tabulation of the following information for all
Material drillholes:
* easting and northing of the drillhole collar
* elevation or RL (elevation above sea level in metres)
of the drillhole collar
* dip and azimuth of the hole
* down hole length and interception depth
* hole length.
--------------------------------------------------------------- -------------------------------------------------------------
Data
aggregation * In reporting Exploration Results, weighting averaging * Exploration results are not being reported for the
methods techniques, maximum and/or minimum grade truncations Mineral Resources areas.
(e.g. cutting of high grades) and cut-off grades are
usually Material and should be stated.
* Metal equivalent values have not been used.
--------------------------------------------------------------- -------------------------------------------------------------
Relationship
between * If the geometry of the mineralisation with respect to * Exploration results are not being reported for the
mineralisation the drillhole angle is known, its nature should be Mineral Resources areas.
widths and reported.
intercept
lengths
* If it is not known and only the down hole lengths are
reported, there should be a clear statement to this
effect.
--------------------------------------------------------------- -------------------------------------------------------------
Diagrams
* Appropriate maps and sections (with scales) and * Relevant diagrams have been included within the
tabulations of intercepts should be included for any Mineral Resource report main body of text.
significant discovery being reported These should
include, but not be limited to a plan view of
drillhole collar locations and appropriate sectional * Exploration results are not being reported for the
views. Mineral Resources areas.
--------------------------------------------------------------- -------------------------------------------------------------
Balanced
reporting * Where comprehensive reporting of all Exploration * Exploration results are not being reported for the
Results is not practicable, representative reporting Mineral Resources areas.
of both low and high grades and/or widths should be
practiced to avoid misleading reporting of
Exploration Results.
--------------------------------------------------------------- -------------------------------------------------------------
Other
substantive * Other exploration data, if meaningful and material, * Exploration results are not being reported for the
exploration should be reported including (but not limited to): Mineral Resources areas.
data geological observations; geophysical survey results;
geochemical survey results; bulk samples - size and
method of treatment; metallurgical test results; bulk
density, groundwater, geotechnical and rock
characteristics; potential deleterious or
contaminating substances.
--------------------------------------------------------------- -------------------------------------------------------------
Further work
* The nature and scale of planned further work (e.g. * Infill and extensional drilling aimed at growing the
tests for lateral extensions or depth extensions or resource and converting Inferred resources to
large-scale step-out drilling). Indicated resources is planned.
--------------------------------------------------------------- -------------------------------------------------------------
Section 3 Estimation and Reporting of Mineral Resources
Criteria JORC Code explanation Commentary
Database
integrity * Measures taken to ensure that data has not been * The drillhole database is managed in-house by company
corrupted by, for example, transcription or keying geologists using Maxwell's Datashed Data Management
errors, between its initial collection and its use System.
for Mineral Resource estimation purposes.
* It has been validated by several company geologists
* Data validation procedures used. and database administrators.
* Data has been imported from current and historical
data files.
* Source data for historical drilling has been verified
as being drilled by Andromeda Metals and imported
directly into Datashed.
* Additional data validation, by Optiro, included
checking for out of range assay data and overlapping
or missing intervals.
------------------------------------------------------------- ----------------------------------------------------------------
Site visits
* Comment on any site visits undertaken by the * Mrs C Standing has not visited the Wudinna Gold
Competent Person and the outcome of those visits. Project.
------------------------------------------------------------- ----------------------------------------------------------------
Geological
interpretation * Confidence in (or conversely, the uncertainty of) the * The weathering interpretation has been used to guide
geological interpretation of the mineral deposit. the segregation of the mineralisation into primary
and supergene zones, which have been treated
separately in the estimation.
* Nature of the data used and of any assumptions made.
* As the host lithology is relatively homogenous, this
* The effect, if any, of alternative interpretations on has not been used to guide the primary mineralisation
Mineral Resource estimation. interpretation.
* The use of geology in guiding and controlling Mineral * These resource estimates investigate an alternative
Resource estimation. interpretation to the 2016 (Barns) and 2017 (White
Tank and Baggy Green) resource estimates.
* The factors affecting continuity both of grade and
geology.
------------------------------------------------------------- ----------------------------------------------------------------
Dimensions
* The extent and variability of the Mineral Resource * The Barns resource has an extent of 400 mN by 250 mE
expressed as length (along strike or otherwise), plan and is up to 200 m deep.
width, and depth below surface to the upper and lower
limits of the Mineral Resource.
* The White Tank resource has an extent of 250mN by 150
mE and is up to 120 m deep.
* The Baggy Green resource has two areas of
mineralisation with extents of 200 mN by 400 mE and
150 mN by 300 mE. The mineralisation extends to a
depth of 200 m.
------------------------------------------------------------- ----------------------------------------------------------------
Estimation and
modelling * The nature and appropriateness of the estimation * Data analysis and estimation was undertaken using
techniques technique(s) applied and key assumptions, including Snowden Supervisor and Datamine software.
treatment of extreme grade values, domaining,
interpolation parameters and maximum distance of
extrapolation from data points. If a computer * Drillhole sample data was flagged from mineralised
assisted estimation method was chosen include a interpretations.
description of computer software and parameters used.
* Mineralisation interpretation were extended to half
* The availability of check estimates, previous the drill spacing and up to 15 m along strike.
estimates and/or mine production records and whether
the Mineral Resource estimate takes appropriate
account of such data. * Sample data was composited to a 1 m downhole length.
* The assumptions made regarding recovery of * The data has a moderate to high coefficient of
by-products. variation and high-grade outliers are present.
Top-cut grades of 4 to 19 g/t gold were applied to
the supergene mineralisation and 19 to 25 g/t gold to
* Estimation of deleterious elements or other non-grade the fresh mineralisation. The top-cut grades were
variables of economic significance (e.g. sulphur for selected by examining histograms, log probability
acid mine drainage characterisation). plots, population disintegration.
* In the case of block model interpolation, the block * The Mineral Resources were estimated by Mining Plus
size in relation to the average sample spacing and in 2016 (Barns) and 2017 (White Tank and Baggy
the search employed. Green). These resources were interpreted using a
higher nominal cut-off grade and have different
letteral extents and mineralisation continuity
* Any assumptions behind modelling of selective mining orientations. The global difference is small (5% more
units. contained gold in the 2019 model) and the tonnage and
grade variances for the individual deposits are
consistent with the differences applied to the
* Any assumptions about correlation between variables. interpretation and resource estimation process.
* Description of how the geological interpretation was * No assumptions have been made regarding the recovery
used to control the resource estimates. of by-products.
* Discussion of basis for using or not using grade * Only gold has been estimated.
cutting or capping.
* Gold mineralisation continuity was interpreted from
* The process of validation, the checking process used, variogram analyses to have along strike (or
the comparison of model data to drillhole data, and down-plunge) ranges of 26 m to 53 m, across strike
use of reconciliation data if available. (or down-dip) ranges of 42 m to 75 m and vertical (or
perpendicular to the mineralisation plane) of 4.5 to
13 m.
* Grade estimation at Barns and White Tank was into
parent blocks of 10 mE by 10 mN on 4 m benches and at
Baggy Green was into a parent block of 20 mE by 20 mN
on 5 m benches. Block sizes were selected based on
kriging neighbourhood analysis.
* Estimation was carried out using ordinary kriging at
the parent block scale.
* The search ellipses were oriented within the plane of
the mineralisation.
* Three estimation passes were used; the first search
was based upon the variogram ranges in the three
principal directions; the second search was two times
the initial search and the third search was five to
six times the second search, with reduced sample
numbers required for estimation.
* At Barns, around 62% of the block grades were
estimated in the first pass, 29% in the second pass
and 9% in the third search pass. At White Tank,
around 81% of the block grades were estimated in the
first pass, 17% in the second pass and 2% in the
third search pass. At Baggy Green, around 21% of the
block grades were estimated in the first pass, 43% in
the second pass and 35% in the third search pass.
* The estimated gold block model grades were visually
validated against the input drillhole data,
comparisons were carried out against the drillhole
data and by northing, easting and elevation slices.
Moisture
* Whether the tonnages are estimated on a dry basis or * Tonnes have been estimated on a dry basis.
with natural moisture, and the method of
determination of the moisture content.
Cut-off
parameters * The basis of the adopted cut-off grade(s) or quality * The Barns, Baggy Green and White Tank Mineral
parameters applied. Resource estimates have been reported at a cut-off
grade of 0.5 g/t gold, which is considered
appropriate for the likely open pit mining method.
------------------------------------------------------------- ----------------------------------------------------------------
Mining factors
or assumptions * Assumptions made regarding possible mining methods, * Planned extraction is by open pit mining.
minimum mining dimensions and internal (or, if
applicable, external) mining dilution. It is always
necessary as part of the process of determining * Mining factors such as dilution and ore loss have not
reasonable prospects for eventual economic extraction been applied.
to consider potential mining methods, but the
assumptions made regarding mining methods and
parameters when estimating Mineral Resources may not
always be rigorous.
------------------------------------------------------------- ----------------------------------------------------------------
Metallurgical
factors or * The basis for assumptions or predictions regarding * No metallurgical assumptions have been built into the
assumptions metallurgical amenability. It is always necessary as resource models.
part of the process of determining reasonable
prospects for eventual economic extraction to
consider potential metallurgical methods, but the
assumptions regarding metallurgical treatment
processes and parameters made when reporting Mineral
Resources may not always be rigorous.
------------------------------------------------------------- ----------------------------------------------------------------
Environmental
factors or * Assumptions made regarding possible waste and process * No assumptions have been made regarding waste and
assumptions residue disposal options. It is always necessary as process residue.
part of the process of determining reasonable
prospects for eventual economic extraction to
consider the potential environmental impacts of the
mining and processing operation.
------------------------------------------------------------- ----------------------------------------------------------------
Bulk density
* Whether assumed or determined. If assumed, the basis * A total of 255 bulk density determinations have been
for the assumptions. If determined, the method used, undertaken at Barns on either historical or recent
whether wet or dry, the frequency of the measurements, drillholes.
the nature, size and representativeness of the
samples.
* The Barns deposit is 1 km north of White Tank and the
bulk density determinations are considered valid for
* The bulk density for bulk material must have been White Tank.
measured by methods that adequately account for void
spaces (vugs, porosity, etc), moisture and
differences between rock and alteration zones within * A total of 185 bulk density determinations have been
the deposit. undertaken at Baggy Green on either historical or
recent drillholes.
* Discuss assumptions for bulk density estimates used
in the evaluation process of the different materials. * Average values have been calculated from the dataset
and applied to the resource model based on the
oxidation/weathering state and lithologies in the
area
* Bulk density measurements were calculated by water
displacement method.
* Density values assigned to the resource model range
from 2.52 t/m(3) to 2.73 t/m(3) .
------------------------------------------------------------- ----------------------------------------------------------------
Classification
* The basis for the classification of the Mineral * The Mineral Resources have been classified on the
Resources into varying confidence categories. basis of confidence in geological and grade
continuity and taking into account data quality, data
density and confidence in the grade estimation (using
* Whether appropriate account has been taken of all the modelled grade continuity and the slope of the
relevant factors (i.e. relative confidence in regression as criteria).
tonnage/grade estimations, reliability of input data,
confidence in continuity of geology and metal values,
quality, quantity and distribution of the data). * The Mineral Resources at White Tank and Baggy Green
have been classified as Inferred.
* Whether the result appropriately reflects the
Competent Person's view of the deposit. * Indicated Mineral Resources have been defined at
Barns within four of the fresh mineralisation domains
in areas where drill spacing is generally 20 mE by 50
m or less and the resources are above 40 mRL.
* Inferred Mineral Resources have been defined at Barns
in areas where extension of mineralisation is
supported by the drilling.
* The classification considers all available data and
quality of the estimate and reflects the Competent
Person's view of the deposit.
------------------------------------------------------------- ----------------------------------------------------------------
Audits or
reviews * The results of any audits or reviews of Mineral * The 2019 Mineral Resource estimates for Barns, White
Resource estimates. Tank and Baggy Green have not yet been audited by an
external party.
* Optiro understands the SRK consulting will be
reviewing the Mineral Resource estimates for Cobra
Resources PLC.
------------------------------------------------------------- ----------------------------------------------------------------
Discussion of
relative * Where appropriate a statement of the relative * The assigned classification of Indicated and Inferred
accuracy/ accuracy and confidence level in the Mineral Resource reflects the Competent Person's assessment of the
confidence estimate using an approach or procedure deemed accuracy and confidence levels in the Mineral
appropriate by the Competent Person. Resource estimate.
* The statement should specify whether it relates to * The statement relates to global estimates of tonnes
global or local estimates, and, if local, state the and grade.
relevant tonnages, which should be relevant to
technical and economic evaluation.
* No production data exists for the Wudinna Project
gold deposits.
------------------------------------------------------------- ----------------------------------------------------------------
This information is provided by RNS, the news service of the
London Stock Exchange. RNS is approved by the Financial Conduct
Authority to act as a Primary Information Provider in the United
Kingdom. Terms and conditions relating to the use and distribution
of this information may apply. For further information, please
contact rns@lseg.com or visit www.rns.com.
END
DRLKELFBKEFZBBL
(END) Dow Jones Newswires
May 07, 2019 02:01 ET (06:01 GMT)
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