REG - Xtract Resources plc - Bushranger ore pre-concentration study results

Xtract ResourcesAnnouncement

08/10/2024 07:00

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RNS Number : 2658H  Xtract Resources plc  08 October 2024

 

For immediate release

 

8 October 2024

 

Xtract Resources Plc

("Xtract" or the "Company")

Encouraging Results Obtained from Ore Pre-Concentration Study

for Bushranger Copper-Gold Project

 

The Board of Xtract Resources Plc ("Xtract" or the "Company") is pleased to
announce the results of a metallurgical study by Altrius Consulting which
investigated three methods to pre-concentrate copper-gold mineralisation from
the Racecourse Mineral Resource on the Bushranger Porphyry Copper-Gold Project
("the Project") in central New South Wales, Australia.  The objective of ore
pre-concentration is to reduce the operating costs for producing a copper-gold
mineral concentrate from the Racecourse Mineral Resource.

 

Highlights

 

·    An earlier Altrius review (refer to RNS dated 18 June 2024) concluded
that Bushranger mineralisation was not amenable to upgrade by the Tomra ore
sorting method, but recommended investigation of alternative pre-concentration
technologies which could significantly improve project economics.

 

·    Xtract therefore investigated the effectiveness of "Pre-Screening",
"Gravity Separation" and "Coarse Particle Flotation" as techniques to
pre-concentrate the mineralisation from the Bushranger Mineral Resource.

 

·    Mineralisation from drill holes BRDD21-036, BRDD22-053, BRDD21-022
were combined into two composite samples, with one sample being used for
Pre-Screening and Gravity Separation tests, while the second sample was used
for the Coarse Particle Flotation ("CPF") test work.

 

·    CPF test work, using the NovaCell(TM) Kinetic Test Work, showed
encouraging results with 78% of the copper mineralisation recovered into only
5% of the mass, with the head grade of the composite sample of 0.19% Cu being
upgraded into a pre-concentrate product of 2.8% Cu.

 

·    NovaCell(TM) coarse particle flotation also recovered 30% more copper
than conventional flotation.

 

·    By contrast, upgrading of the Racecourse mineralisation by
pre-screening and simple dense media separation did not achieve positive
results, probably due to the disseminated nature of the chalcopyrite within
the host rock.

 

·    In a further positive development, the Company has been advised that
EL5574, the main tenement encompassing the Bushranger copper-gold deposits,
has been renewed in full for an additional three years until 4 June 2027.

 

Colin Bird, Executive Chairman said: "The pre-concentrate test work on
copper-gold mineralisation from the Racecourse deposit on the Bushranger
Project has shown encouraging results with coarse particle flotation using
NovaCell(TM) technology, demonstrating the potential to increase the grade of
copper concentrates and recover up to 30% more copper.  The NovaCell(TM)
process captured 78% of the originally contained copper while rejecting 95% of
the original rock mass and this will have significantly positive effects on
the costs to process the copper-gold mineralisation from the Racecourse
Mineral Resource.  As the average grade of the world's overall copper
resources continues to fall, ore pre-concentration will become an increasingly
important part of the process to allow copper mineral resources to be
economically mined and it is pleasing to see that the copper-gold
mineralisation from the Racecourse deposit responds well to ore
pre-concentration. We will carry out more detailed test work on the most
appropriate methodologies with a low-cost budget and if appropriate introduce
the revised technical parameters into the financial model. At current and
forecasted copper prices, the project is demonstrating the potential to be one
of the next global contributors to the copper deficit. We will keep
shareholders informed on the technical and financial results as they progress"

 

Ore Pre-Concentration Test Work Program on Mineralisation from the Racecourse
Mineral Resource

From July 2021 until July 2022, Xtract completed a Phase 2 diamond drilling
programme at the Racecourse and Ascot prospects on the Bushranger Project in
central New South Wales, Australia.  Following conclusion of the Phase 2
drilling program independent consultants, "The Measured Group", based in
Brisbane, Australia reported a Mineral Resource of 512Mt @ 0.22% CuEq, at a
cut-off of 0.1% CuEq*, and classified as Inferred and Indicated in accordance
with JORC (2012) (refer to RNS 23 November 2022), for the Racecourse Prospect.

 

[*CuEq % = (Cu%) + (Au g/t * 0.6577)% + (Ag g/t * 0.008769) %

Cu Price = US$8800/t, Au Price = US$1800/oz, Ag Price = US$24/oz]

 

Mining studies by Optimal Mining on the Bushranger Gold-Copper Project,
completed in 2022 and 2023, concluded that a minimum production rate of 20
Mtpa, and copper price in excess of US$10,000/tonne, are required to generate
a positive Net Present Value ("NPV") from open pit mining of the Racecourse
Mineral Resource (refer to RNS 7 March 2023). To assess the ability of ore
pre-concentration to enhance project economics, Xtract contracted Altrius
Consulting ("Altrius") to undertake a review of the applicability of ore
pre-concentration methods to the Racecourse prospect copper-gold
mineralisation (refer to RNS 20 July 2023).  The Altrius review concluded
that ore-concentration technologies may benefit processing of the Racecourse
copper-gold mineralisation, with a subsequent potential improvement to the
overall project NPV.  Altrius recommended that the following
pre-concentration techniques had the potential to concentrate the valuable
component of the copper-gold mineralisation into a smaller mass for downstream
processing (in order of preference):

 

·    Coarse Particle Flotation ("CPF")

·    Gravity Separation via Dense Media Separation ("DMS")

·    Pre-Screening of run-of-mine ore

 

Metallurgical test work samples from drill holes BRDD21-036 (168m @ 0.14% Cu
& 0.06g/t Au), BRDD22-053 (320m @ 0.11% Cu & 0.06g/t Au) and
BRDD21-022 (144m @ 0.25% Cu & 0.02g/t Au) were combined into two composite
samples.  A 94kg composite sample from drill hole BRDD22-053 (309m to 325m
and 383m to 457m), with an average copper grade of 0.18% Cu, was used for the
Coarse Particle Flotation test work using NovaCell(TM) technology.  A
composite sample from drill holes BRDD21-036 and BRDD21-022, with an average
copper grade of 0.24% Cu and 0.05g/t Au, was used for the Gravity Separation
and Pre-Screening test work.

 

Coarse Particle Flotation Using NovaCell(TM) Technology

 

To test the applicability of the NovaCell(TM) technology to process
mineralisation from the Racecourse Mineral Resource, the combined sample with
head grade of 0.18% Cu from drill hole BRDD22-053, was subjected to a Coarse
Particle Flotation test.  The flotation sample was crushed to achieve a
flotation feed of P(100) of 600µm, following which the pulp was diluted to
achieve a pulp density of 32% solids.  A standard flotation scheme was
adopted with a PAX collector (80g/t) and MIBC as the frother.  Three
concentrates were recovered over a total flotation time of 5 minutes.

 

Using the NovaCell(TM) process, Coarse Particle Flotation delivered
encouraging results with 80% of the copper in the original combined sample of
0.18% Cu, being recovered into a pre-concentrated product of 2.1% Cu.  The
mass yield to concentrate was 11%.  The results of the Coarse Particle
Flotation test using NovaCell(TM) technology are given in Table One.

 

Table 1 - Coarse Particle Flotation Test using NovaCell(TM) technology

 

 Sample                          Assayed Grade               Recovery (%)        Mass Yield
                         Cu (%)  Au (g/t)       S (%)  Cu    Au            S     (%)
 Feed                    0.18    N/A            0.454  -     -             -     100
 Concentrate 1 (Froth)   2.07    N/A            5.19   70.5  N/A           71.7  6.3
 Concentrate 2 (Screen)  0.36    N/A            1.09   9.1   N/A           11.1  4.6
 Tails                   0.04    N/A            0.09   20.4  N/A           17.2  89.1

During the 350μm scoping test, it was observed that an excessively weak
concentrate was produced, with this a possible contributor to the reduced
copper recovery. Following on from this, a NovaCell(TM) kinetic test was
implemented, using a marginally finer grind size (P80 of 350μm) with a
reduced frother addition, to generate a more consistent froth phase.

This kinetic test yielded no marked improvement in recovery with 78% of the
copper in head (0.19%) recovered into a concentrate containing 2.8% copper.
The finer grind did however improve liberation and the mass yield to
concentrate reduced from 11% to 5%. The finer grind also resulted in an
increase in flotation kinetics, with the original scoping test (P(80) 470μm)
requiring 40 minutes to achieve 80% copper recovery, compared with the 25
minutes required to achieve 78% copper recovery at a P(80) 350μm. Results
from the repeat coarse particle flotation test are summarised in Table 2.

 

Table 2 - NovaCell(TM) Kinetic Test Work Summary

 

 Sample                         Assayed Grade               Recovery (%)        Mass Yield
                        Cu (%)  Au (g/t)       S (%)  Cu    Au            S     (%)
 Feed                   0.19    N/A            0.469  -     -             -     100
 Concentrate 1 (Froth)  2.80    N/A            6.94   78.3  N/A           79.1  5.4
 Tails                  0.04    N/A            0.09   21.7  N/A           20.9  94.6

 

In order to compare the results of the Coase Particle Flotation Test using
NovaCell(TM) technology to conventional flotation a parallel standard rougher
flotation test was conducted, at the same grind size, following which the pulp
was diluted to achieve a pulp density of 31% solids. A standard flotation
scheme was adopted with a PAX collector (80g/t) and MIBC as the frother.
Three concentrates were recovered over a total flotation time of 5 minutes.

 

The results of the conventional flotation test are given in Table 3.

 

 

 

Table 3 - Conventional Flotation Test

 

 Sample                         Assayed Grade               Recovery (%)        Mass Yield
                        Cu (%)  Au (g/t)       S (%)  Cu    Au            S     (%)
 Feed                   0.18    N/A            0.426  -     -             -     100
 Concentrate 1 (Froth)  4.63    N/A            11.19  50.5  N/A           51.4  2.0
 Tails                  0.09    N/A            0.211  49.6  N/A           17.2  98.0

 

The coarse particle flotation mechanical test yielded a copper recovery of
51%, from a head grade of 0.18% Cu, into a concentrate of 4.6% Cu.  The mass
yield was 2%.

 

In comparison to a conventional mechanical flotation process, Coarse Particle
Flotation using the NovaCell(TM) technology yielded superior flotation results
with overall copper recovery being 30% higher using the NovaCell(TM)
technology.

 

Pre-Screening

 

Pre-screening is a pre-concentration technique which exploits the natural
deportment of mineralisation into finer size fractions following initial
crushing in a mineral processing plant.  The objective is to reject course,
unmineralized material into oversize waste and concentrate the "enriched"
finer sized material.  This technique is most applicable to mineralisation
associated with natural fracture patterns or with mineralisation occurring on
mineral / waste grain boundaries.

 

To test the applicability of pre-screening to the copper-gold mineralisation
of the Racecourse Mineral Resource, a composite 118kg sample (Comp BRDD21) was
produced from drill holes BRDD21-022 (290m to 350m) and BRDD21-036 (121m to
169m).  The average copper grade of the composite sample was 0.21% Cu.

 

The composite sample was subjected to simple screen sizing to establish if any
upgrading of the sample could be achieved by crushing the sample to a P(100)
of 12mm.  The crushed product was then screened, using a 6mm screen, with the
oversize (-12mm to +6mm) and undersize fractions subjected to assaying to
determine the deportment of copper and gold into the two size fractions.  The
results of the pre-screening test work are given in Table 4.

 

Table 4 - Pre-Screening Test Work Summary of +6mm

 

 Sample       Size Fraction   Mass (g)  Assays            Distribution  (%)
                                        Au (g/t)  Cu (%)  Au            Cu
 Comp BRDD21  -12 mm to +6mm  10,362    0.01      0.15    18.3          57.7
 Comp BRDD21  -6mm to +3.5mm  1,785     0.12      0.19    37.8          12.4
 Comp BRDD21  -3.5mm to +1mm  1,631     0.04      0.23    11.5          13.5
 Comp BRDD21  +38µm           1,053     0.08      0.34    14.9          13.1
 Comp BRDD21  -39µm           168       0.59      0.54    17.5          3.3

 

Analysis of the pre-screening results shown above in Table 4 concluded that
upgrading the copper content into a fines fraction could not be achieved by
crushing the sample to 100% passing a size of 12mm.  The +6mm size fraction
returned a copper grade of 0.15% whilst the -6mm fraction returned a copper
grade of 0.23%, in line with the head sample assay of 0.24% Cu.  Regarding
the metal distribution 57.7% of the copper reported to the +6mm size fraction
and 42.3% reported to the -6mm size fraction.

 

In an attempt to improve pre-concentration of copper by pre-screening, finer
crush sizes were tested.  The composite sample was crushed to P(100) of 6mm
and screened at 3mm and also to P(100) of 3mm and screened at 1mm.  Neither
of the two finer crush sizes resulted in any improvement in the copper
deportment to the finer size fraction.  Therefore, it is concluded that
simple pre-screening is not a technique appropriate for pre-concentrating the
copper-gold mineralisation from the Racecourse Mineral Resource.

 

Dense Media Separation

 

Dense media separation (DMS), is a gravity separation process whereby
particles are sorted primarily according to their densities, by introducing
particles to a heavy liquid.  Particles which are lighter than the density of
the heavy liquid rise and a referred to as "floats".  Particles heavier than
the density of the heavy liquid fall and a referred to as "sinks".  Particles
of sulphide mineralisation are usually more dense than the surrounding barren
host rock and hence should preferentially report to the "sinks" fraction,
allowing the mineralisation to be pre-concentrated.

 

To test the applicability of DMS to pre-concentrating the copper-gold
mineralisation from the Racecourse Mineral Resource, the -3.35mm size fraction
originating from the pre-screening test work was subjected to heavy liquid DMS
separation using a heavy liquid of density 3.3 t/m(3).  The results are
summarised in Table 5.

 

Table 5 - Dense Media Separation Pre-Concentration Results Summary

 

 Sample       Size Fraction             Mass (g)          Distribution  (%)
                                 Feed   Sinks     Floats  Sinks         Floats
 Comp BRDD21  -3.35mm to +1.0mm  485.5  1.4       484.1   0.3           99.7
 Comp BRDD21  -1.0mm to +38µm    236.7  3.1       233.6   1.3           98.7

 

 

Using a heavy liquid of density 3.3 t/m(3), only 0.3% of the rock mass
reported to the "sinks" fraction indicating that DMS is not a technique
appropriate to pre-concentrating the copper-gold mineralisation from the
Racecourse Mineral Resource.

 

Conclusions

 

Coarse Particle Flotation test work, using the NovaCell(TM) technology, showed
encouraging results in pre-concentrating the copper-gold mineralisation from
the Racecourse Mineral Resource.  80% of the head grade of the composite
sample of 0.18% Cu was recovered into a pre-concentrated product of 2.1% Cu.
Furthermore, NovaCell(TM) Coarse Particle Flotation delivered superior results
in comparison to conventional floatation, recovering 30% more copper. Hence,
the use of NovaCell(TM) Coarse Particle Flotation should have a positive
effect on the economics of open pit mining the Racecourse Mineral Resource.

 

Simple pre-screening and Dense Media Separation do not appear to be techniques
effective at pre-concentrating the copper-gold mineralisation from the
Racecourse Mineral Resource.

 

Further information is available from the Company's website which details the
company's project portfolio as well as a copy of this
announcement: www.xtractresources.com

 

The information contained within this announcement is deemed by the Company to
constitute inside information as stipulated under the Market Abuse Regulations
(EU) No. 596/2014 as it forms part of UK Domestic Law by virtue of the
European Union (Withdrawal) Act 2018 ("UK MAR").

 

The person who arranged for the release of this announcement on behalf of the
Company was Colin Bird, Executive Chairman and Director.

 

Enquiries:

 

 Xtract Resources Plc                               Colin Bird,          +44 (0)20 3416 6471

                                                    Executive Chairman   www.xtractresources.com (http://www.xtractresources.com)

 Beaumont Cornish Limited                           Roland Cornish       +44 (0)207628 3369

 Nominated Adviser and Joint Broker                 Michael Cornish      www.beaumontcornish.co.uk (http://www.beaumontcornish.co.uk)

                                                    Felicity Geidt

 Novum Securities Limited                           Jon Belliss          +44 (0)207 399 9427

 Joint Broker                                       Colin Rowbury        www.novumsecurities.com

 

 

 

 

Qualified Person

Information in this announcement relating to the exploration works has been
reviewed by Edward (Ed) Slowey, BSc, PGeo, a consultant to Xtract. Mr Slowey
is a graduate geologist with more than 40 years' relevant experience in
mineral exploration and mining, a founder member of the Institute of
Geologists of Ireland and is a Qualified Person under the AIM rules. Mr
Slowey has reviewed and approved the geological content of this announcement.

 

Qualified Person

In accordance with AIM Note for Mining and Oil & Gas Companies, June 2009
("Guidance Note"), Colin Bird, CC.ENG, FIMMM, South African and UK Certified
Mine Manager and Director of Xtract Resources plc, with more than 40 years'
experience mainly in hard rock mining, is the qualified person as defined in
the Guidance Note of the London Stock Exchange, who has reviewed the technical
information contained in this press release.

 

Mineral Reserves and Resources

The Company estimates and discloses mineral reserves and resources using the
definitions adopted by JORC.  Further details are available at
www.jorc.org.  See the "Glossary of Geological and Mining Terms" for complete
definitions of mineral reserves and mineral resources.

About Mineral Resources

Mineral resources are not mineral reserves and do not have demonstrated
economic viability but do have reasonable prospect for economic extraction.
They fall into three categories: measured, indicated, and inferred. The
reported mineral resources are stated inclusive of mineral reserves.
Measured and indicated mineral resources are sufficiently well-defined to
allow geological and grade continuity to be reasonably assumed and permit the
application of technical and economic parameters in assessing the economic
viability of the mineral resource. Inferred mineral resources are estimated on
limited information not sufficient to verify geological and grade continuity
or to allow technical and economic parameters to be applied.  Inferred
mineral resources are too speculative geologically to have economic
considerations applied to them. There is no certainty that mineral resources
of any category will be upgraded to mineral reserves.

Important Information about Mineral Reserve and Resource Estimates

Whilst the Company takes all reasonable care in the preparation and
verification of the mineral reserve and resource figures. the figures are
estimates based in part on forward-looking information. Estimates are based on
management's knowledge, mining experience, analysis of drilling results, the
quality of available data and management's best judgment. They are, however,
imprecise by nature, may change over time, and include many variables and
assumptions including geological interpretation, commodity prices and currency
exchange rates, recovery rates, and operating and capital costs. There is no
assurance that the indicated levels of metal will be produced, and the Company
may have to re-estimate the mineral reserves based on actual production
experience. Changes in the metal price, production costs or recovery rates
could make it unprofitable to operate or develop a particular deposit for a
period of time.

Forward Looking Statements

Certain statements in this announcement, are, or may be deemed to be, forward
looking statements. Forward looking statements are identified by their use of
terms and phrases such as ''believe'', ''could'', "should" ''envisage'',
''estimate'', ''intend'', ''may'', ''plan'', ''will'' or the negative of
those, variations or comparable expressions, including references to
assumptions. These forward-looking statements are not based on historical
facts but rather on the Directors' current expectations and assumptions
regarding the Company's future growth, results of operations, performance,
future capital and other expenditures (including the amount, nature and
sources of funding thereof), competitive advantages, business prospects and
opportunities. Such forward looking statements reflect the Directors' current
beliefs and assumptions and are based on information currently available to
the Directors. A number of factors could cause actual results to differ
materially from the results discussed in the forward-looking statements
including risks associated with vulnerability to general economic and business
conditions, competition, environmental and other regulatory changes, actions
by governmental authorities, the availability of capital markets, reliance on
key personnel, uninsured and underinsured losses and other factors, many of
which are beyond the control of the Company. Although any forward-looking
statements contained in this announcement are based upon what the Directors
believe to be reasonable assumptions, the Company cannot assure investors that
actual results will be consistent with such forward looking statements.

 

Beaumont Cornish Limited ("Beaumont Cornish") is the Company's Nominated
Adviser and is authorised and regulated by the FCA. Beaumont Cornish's
responsibilities as the Company's Nominated Adviser, including a
responsibility to advise and guide the Company on its responsibilities under
the AIM Rules for Companies and AIM Rules for Nominated Advisers, are owed
solely to the London Stock Exchange. Beaumont Cornish is not acting for and
will not be responsible to any other persons for providing protections
afforded to customers of Beaumont Cornish nor for advising them in relation to
the proposed arrangements described in this announcement or any matter
referred to in it.

TECHNICAL GLOSSARY

The following is a summary of technical terms:

 

 "Ag"                          Silver
 "Au"                          Gold
 "Cu"                          Copper
 "CuEq"                        Copper equivalent grade, calculated using assumed metal prices for copper,
                               gold and other metals

 "Indicated Mineral Resource"  That part of a Mineral Resource for which quantity, grade (or quality),
                               densities, shape and physical characteristics are estimated with sufficient
                               confidence to allow the application of Modifying Factors in sufficient detail
                               to support mine planning and evaluation of the economic viability of the
                               deposit. Geological evidence is derived from adequately detailed and reliable
                               exploration, sampling and testing gathered through appropriate techniques from
                               locations such as outcrops, trenches, pits, workings and drill holes, and is
                               sufficient to assume geological and grade (or quality) continuity between
                               points of observation where data and samples are gathered. (JORC 2012)

 "Inferred Mineral Resource"   That part of a Mineral Resource for which quantity and grade (or quality) are
                               estimated on the basis of limited geological evidence and sampling. Geological
                               evidence is sufficient to imply but not verify geological and grade (or
                               quality) continuity. It is based on exploration, sampling and testing
                               information gathered through appropriate techniques from locations such as
                               outcrops, trenches, pits, workings and drill holes. (JORC 2012)

 "MIBC"                        Methyl isobutyl carbinol

 "mineralisation"              Process of formation and concentration of elements and their chemical

                             compounds within a mass or body of rock

                             Microns
 "µm"

 "PAX"                         Potassium amyl xanthate

 "porphyry"                    A deposit of disseminated copper minerals in or around a large body of
                               intrusive rock

 "Mtpa"                        Million tonnes per annum

ENDS

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