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
NovaCellTM 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.
·
NovaCellTM 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
NovaCellTM
technology, demonstrating the potential
to increase the grade of copper concentrates and recover up to 30%
more copper. The NovaCellTM
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 NovaCellTM
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 NovaCellTM
Technology
To test the applicability of
the NovaCellTM 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
P100 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
NovaCellTM 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
NovaCellTM technology are given in Table One.
Table 1 - Coarse Particle Flotation
Test using NovaCellTM
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 NovaCellTM 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 (P80 470μm) requiring 40 minutes to achieve 80%
copper recovery, compared with the 25 minutes required to achieve
78% copper recovery at a P80 350μm. Results from the
repeat coarse particle flotation test are summarised in Table
2.
Table 2 - NovaCellTM
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
NovaCellTM 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 NovaCellTM technology yielded superior
flotation results with overall copper recovery being 30% higher
using the NovaCellTM
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 P100 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
P100 of 6mm and screened
at 3mm and also to P100 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/m3. 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/m3, 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 NovaCellTM 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, NovaCellTM
Coarse Particle Flotation delivered superior
results in comparison to conventional floatation, recovering 30%
more copper. Hence, the use of NovaCellTM 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,
Executive Chairman
|
+44 (0)20 3416 6471
www.xtractresources.com
|
Beaumont Cornish Limited
Nominated Adviser and Joint Broker
|
Roland Cornish
Michael Cornish
Felicity Geidt
|
+44 (0)207628 3369
www.beaumontcornish.co.uk
|
Novum Securities Limited
Joint Broker
|
Jon Belliss
Colin Rowbury
|
+44 (0)207
399 9427
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"
"µm"
|
Process of formation and
concentration of elements and their chemical compounds within a
mass or body of rock
Microns
|
"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