NorthWest Copper (“NorthWest” or “the Company”) (TSX-V: NWST) is
pleased to report that positive metallurgical results have
been achieved from the first modern metallurgical work completed on
samples from the Lorraine copper-gold-silver deposit, located in
north-central British Columbia. Highlights of the test work
include:
- High batch cleaner flotation recoveries of up to 94%, 71% and
92% for copper (Cu), gold (Au) and silver (Ag), respectively.
- High metal recoveries at a relatively coarse primary grind size
of 80% passing 150 microns.
- Production of Cu concentrates with 31 to 54% Cu that contain
7.4 to 25.4 g/t Au and 152 to 405 g/t Ag, and also up to 1.64 g/t
palladium (Pd) and anomalous platinum (Pt).
- Low concentrations of potentially deleterious trace elements in
the Cu concentrate.
“These metallurgical results demonstrate that
mineralization in our Lorraine deposit can potentially produce high
metal recoveries to a clean, high-grade salable copper
concentrate”, stated Tyler Caswell, Vice President Exploration for
NorthWest. “The results also highlight several opportunities for
optimizing future metallurgical work, improving metal recoveries
and evaluating other beneficial metal recovery-energy consumption
trade-offs to positively impact future project evaluation.”
The test work program described below was
designed by Base Metallurgical Laboratories Ltd. (“Base Met”) and
BOMENCO Minerals Engineering Corp. The work was executed by Base
Met in their facilities in Kamloops, BC. Both groups are
independent of NorthWest. Samples for compositing were collected by
the NorthWest Copper geology team.
Composite SamplesThe
metallurgical program tested five composite samples that ranged
from 19.6 kg to 37.4 kg in size, and included one from the
Bishop Zone (BZC) and four from the Lower Main Zone (LMC1-4; Table
1). Two composites were created from half-split historical drill
core, which was deemed suitable for scoping test work because it
was intact, had been well stored, and had very low pyrite
concentration that minimized surface oxidation of sulphide
minerals. The remaining three samples are from the Lower Main Zone
and comprised assay coarse reject material from drill holes
completed by Northwest in 2022. These crushed materials have
a large surface area compared to intact core, and to prevent
surface oxidation of the sulphide minerals these three samples were
placed in frozen storage immediately after routine geochemical
analyses. The samples contain disseminated copper mineralization
hosted by pyroxenite and syenite, which are the predominant
material types in the Lorraine deposit. The samples were selected
to be reasonable geological and geochemical representations of the
main styles of mineralization at Lorraine, as currently understood,
and therefore are interpreted to be reasonable for use in the
scoping metallurgical test work reported here. Copper
concentrations in the five composites range from approximately
average (0.61 % Cu) to higher grade (1.21% Cu), in comparison to
the average grade of 0.55% Cu in the indicated mineral resources
estimate at the Lorraine deposit.1
Table 1. Composite characteristics and head
assay grades.
Composite |
Material Used |
Rock Type |
Mass(kg) |
Head Assay |
Cu% |
Au g/t |
Ag g/t |
Pt g/t |
Pd g/t |
S% |
Bishop Zone (BZC) |
Half core |
pyroxenite |
36.5 |
1.15 |
0.14 |
9.60 |
<0.01 |
0.03 |
0.51 |
Lower Main Zone (LMZ1) |
Half core |
syenite |
31.5 |
1.21 |
0.86 |
8.80 |
<0.01 |
0.01 |
0.64 |
Lower Main Zone (LMZ2) |
CoarseRejects |
syenite |
26.7 |
0.79 |
0.31 |
4.80 |
<0.01 |
0.01 |
1.16 |
Lower Main Zone (LMZ3) |
CoarseRejects |
syenite & monzonite |
37.4 |
0.77 |
0.36 |
6.00 |
<0.01 |
0.01 |
0.38 |
Lower Main Zone (LMZ3) |
CoarseRejects |
pyroxenite |
19.6 |
0.61 |
0.30 |
3.40 |
<0.01 |
0.03 |
0.46 |
|
|
|
|
|
|
|
|
|
|
Summary of Recovery TestsTwo
sets of five-stage rougher flotation tests compared results from
typical porphyry (75 µm) and coarse (150 µm) primary K80 grind
sizes (Table 2). Copper recoveries of 94-98% were achieved at the
finer grind, whereas the coarse grind recovered 90-99% Cu (Figure
1). Overall recoveries at the two grind sizes ranged from 66-90%
for Au, and from 86-97% for Ag. The results support potential to
beneficiate Lorraine mineralization at a relatively coarse,
possibly energy-saving grind size without a large impact on metal
recovery, and this opportunity can be assessed by future grind size
versus metal recovery trade off studies. A gravity test on 150 µm
grind size material recovered 4-24% of gold to a gravity
concentrate, and when the gravity tails were treated by rougher
flotation there was a modest improvement in overall gold recovery,
providing an additional possible avenue to further improve
performance.
Table 2. Summary of rougher flotation
recoveries.
Comp |
Primary Grind Size (µm K80) |
Recovery (%) |
Cu |
Au |
Ag |
Pt |
Pd |
BZC |
75 |
97.8 |
86.3 |
96.9 |
37.9 |
75.2 |
150 |
99.0 |
89.5 |
97.0 |
35.4 |
75.0 |
LMC1 |
75 |
94.3 |
80.4 |
92.9 |
20.9 |
37.8 |
150 |
89.7 |
70.5 |
85.6 |
31.8 |
38.3 |
LMC2 |
75 |
96.5 |
76.8 |
90.8 |
15.6 |
45.5 |
150 |
95.3 |
82.9 |
85.7 |
29.3 |
50.6 |
LMC3 |
75 |
93.9 |
81.5 |
93.2 |
19.7 |
41.9 |
150 |
93.6 |
85.7 |
88.3 |
20.5 |
47.1 |
LMC4 |
75 |
95.5 |
75.4 |
88.5 |
33.8 |
68.1 |
150 |
91.8 |
66.4 |
88.1 |
38.5 |
62.9 |
|
|
|
|
|
|
|
_______________1 See NI 43-101 technical report titled “Lorraine
Copper-Gold Project NI 43-101 Report & Mineral Resource
Estimate Omineca Mining Division, B.C”, dated September 12, 2022
with an effective date of June 30, 2022, filed under the Company’s
SEDAR+ profile at www.sedarplus.com.
Figure 1. Copper recovery curves for rougher
flotation tests at two primary grind sizes.
Cleaner flotation tests go an important step
beyond rougher tests and more closely simulate concentrate
production potential. Cleaner tests were completed on
material ground to 150 µm for initial rougher flotation, followed
by a regrind targeting a 25 µm size before progressing through
three-stage open circuit cleaner flotation. The samples
performed extremely well (Table 3). The Bishop Zone composite had
Cu, Au and Ag recoveries of 94%, 71% and 92%, respectively, to a
concentrate with 54% Cu, 7.4 g/t Au, and 405 g/t Ag. Samples from
the Lower Main Zone had recoveries of 83-89% Cu, 57-70% Au, and
74-83% Ag to concentrates with 31-49% Cu, 11-25 g/t Au, and 152-360
g/t Ag. The high Cu concentrations in the concentrate (up to 54%
Cu) reflect the hypogene (unweathered) copper sulphide mineralogy
of the mineralization, which in addition to chalcopyrite (~34 wt %
Cu) also includes bornite (~63 wt % Cu) and chalcocite (~80 wt %
Cu). Intriguingly, two samples also returned 1.41 and 1.64
g/t Pd accompanied by significantly anomalous Pt. Analyses of the
five copper concentrates produced by the cleaner flotation tests
demonstrate that Lorraine can produce high quality concentrates
with all trace elements below likely penalty threshold
concentrations.
Table 3. Cleaner concentrate compositions and
recoveries.
Comp |
Cleaner Concentrate Performance |
Assay % or g/t |
Recovery% |
Cu |
Au |
Ag |
Pt |
Pd |
Cu |
Au |
Ag |
Pt |
Pd |
BZC |
54.4 |
7.35 |
405 |
0.21 |
1.41 |
94.2 |
71.2 |
91.5 |
28.8 |
76.1 |
LMC1 |
48.4 |
25.4 |
317 |
0.06 |
0.21 |
83.4 |
57.2 |
78.5 |
10.2 |
27.6 |
LMC2 |
31.3 |
11.3 |
152 |
0.04 |
0.22 |
89.1 |
69.3 |
74.3 |
7.8 |
29.9 |
LMC3 |
48.9 |
22.5 |
360 |
0.08 |
0.38 |
85.6 |
70.1 |
82.5 |
9.1 |
29.9 |
LMC4 |
52.3 |
20.0 |
292 |
0.26 |
1.64 |
87.4 |
64.8 |
79.5 |
19.5 |
53.6 |
|
|
|
|
|
|
|
|
|
|
|
Comminution TestsBond Ball Mill
work indices were measured on each of the five composites to assess
grindability. Results range from 15.0 kWh/t (average hardness) to
20.3 kWh/t (very hard) and are in line with expectations that were
based on core competency and rock mineralogy and texture.
Table 4. Glossary of Terms2
Ball Mill |
A mill in which tumbling steel balls grind larger particles to a
smaller size. |
Comminution |
The breaking of large particles into smaller particles. The most
common comminution processes are crushing and grinding. |
Composite |
A larger sample created by combining several smaller samples. |
Concentrate |
The valuable product from a flotation mineral processing
plant. |
Flotation |
A common mineral recovery process whereby chemicals are added to
water to cause target minerals (such as Cu minerals) to attach to
rising air bubbles, which are then removed to recover the ore
minerals into a concentrate. |
Recovery |
The percentage of the valuable metal present in the feed that
reports to the concentrate. |
|
|
LorraineThe Lorraine deposit is
part of the Lorraine Project. The Lorraine Project covers
56,000 hectares and is located in north-central British Columbia,
280 km northwest of Prince George, BC and approximately 40 km from
NorthWest’s Kwanika-Stardust Project. The Lorraine deposit is
located near the centre of the Project tenure and is a
silica-undersaturated alkalic copper-gold porphyry deposit, which
is the same classification as the Galore Creek and Mount Polley
deposits.3 Mineralization at the Lorraine deposit is hosted mostly
by Early Jurassic syenite and pyroxenite intrusions that are part
of the Duckling Creek Syenite Complex (“DCSC”). A modern, compliant
mineral resource estimate (MRE) was completed in 2022 that includes
indicated resources of 12.952 Mt grading 0.55% Cu and 0.16 g/t Au,
and inferred resources of 45.252 Mt grading 0.43% Cu and 0.10 g/t
Au. 4 As described in previous disclosures, however, gold
concentration is likely understated and silver was not included in
the estimation because many historical drill holes were
inconsistently analyzed for the two metals. The MRE extends to
surface and includes the Lower Main, Upper Main, and Bishop Zones
and intervening rock. Copper sulphides manifest various
combinations of chalcopyrite, bornite and hypogene chalcocite, and
the concentration of pyrite is generally low. Gold and silver,
where analyzed, are spatially related to the copper mineralization,
and elevated concentrations of platinum and palladium have been
reported in several published papers.
_______________2
https://www.911metallurgist.com/blog/mineral-processing-glossary3
Lang et al. (1995) Triassic-Jurassic silica-undersaturated and
silica-saturated alkalic intrusions in the Cordillera of British
Columbia: Implications for arc magmatism. Geology, v. 23, p.
451-454.4 See NI 43-101 technical report titled “Lorraine
Copper-Gold Project NI 43-101 Report & Mineral Resource
Estimate Omineca Mining Division, B.C”, dated September 12, 2022
with an effective date of June 30, 2022, filed under the Company’s
SEDAR+ profile at www.sedarplus.com.
Quality Assurance / Quality
Control (QA/QC) Geochemical analyses reported by Base Met
utilize a variety of analytical methods to optimize results for
specific elements and elemental groups. All analyses were completed
by Base Met, with exception of chlorine and fluorine analysis. Gold
was analyzed by fire assay with AAS finish, whereas
platinum-palladium is based on fire assay with ICP-OES finish.
Sulphur and TOC were measured by LECO. Copper was determined by
single element aqua regia digestion with AAS finish, whereas
silver, arsenic and antimony used an ICP-OES finish. Other trace
elements were measured by aqua regia digestion and ICP-OES
analysis. Whole rock analyses use ICP-OES following total digestion
by lithium metaborate fusion. Chlorine was analyzed by Short Lived
INAA using method code 4F-Cl, and fluorine was determined by Fusion
Specific Ion Electrode analysis (method code 4F-F) at Activation
Laboratories in Ancaster, Ontario. All methods employed certified
reference materials for analytical control.
Drilling completed at Lorraine in 2022 was
supervised by on-site NorthWest personnel who collected and tracked
samples and implemented a full QA/QC program using blanks,
standards and duplicates to monitor analytical accuracy and
precision. The samples were sealed on site and shipped to AGAT
Laboratories (AGAT) in Calgary, Alberta. AGAT’s quality control
system complies with global certifications for Quality ISO
9001:2015. Core samples were analyzed using a combination of AGAT’s
201-071 process for low-level concentrations (ICP-MS/4 Acid
digestion) and higher-level concentrations were finalized with
method 201-097 (Sodium Peroxide Fusion/ICP-OES). Gold assaying was
completed with 202-055, a 30-gram fire assay with ICP finish.
Technical aspects of this news release have been
reviewed, verified, and approved by Tyler Caswell, P.Geo., VP
Exploration of NorthWest, and Matt Bolu, M.Sc., P.Eng., Principal
Metallurgical Engineer, BOMENCO Minerals Engineering Corp, both of
whom are qualified persons as defined by National Instrument 43-101
– Standards of Disclosure for Minerals Projects.
About NorthWest Copper:
NorthWest Copper is a copper-gold explorer with
a pipeline of advanced and early-stage projects in British
Columbia. With a robust portfolio in a tier one jurisdiction,
NorthWest Copper is well positioned to participate fully in a
strengthening global copper market. We are committed to
responsible mineral exploration and are working collaboratively
with First Nations to ensure future exploration and development
incorporates stewardship best practices and traditional land use.
Additional information can be found on the Company’s website
at www.northwestcopper.ca.
On Behalf of NorthWest Copper
Corp. “Tyler Caswell”Vice President, Exploration
For further information, please
contact:
604-683-7790info@northwestcopper.ca
Neither TSX Venture Exchange nor its Regulation Services
Provider (as that term is defined in the policies of the TSX
Venture Exchange) accepts responsibility for the adequacy or
accuracy of this release.
Cautionary Statement Regarding
Forward-Looking Information
This news release contains “forward-looking
information” within the meaning of applicable securities laws. All
statements, other than statements of historical fact, are
forward-looking statements and are based on expectations, estimates
and projections as at the date of this news release. Any statement
that involves discussion with respect to predictions, expectations,
beliefs, plans, projections, objectives, assumptions, future events
or performance (often, but not always using phrases such as
“plans”, “expects”, “is expected”, “budget”, “scheduled”,
“estimates”, “forecasts”, “intends”, “anticipates”, or “believes”
or variations (including negative variations) of such words and
phrases, or state that certain actions, events or results “may”,
“could”, “would”, “might” or “will” be taken, occur or be achieved)
are not statements of historical fact and may be forward-looking
statements. In this news release, forward-looking statements
relate, among other things, to statements with respect to; plans
and intentions of the Company; the potential increase to metal
recoveries, the expected copper concentrate quality, the potential
for reduction in ball mill grinding energy, the expected copper,
gold and silver recoveries, the possibility of adding gold and
silver in future Mineral Resource Estimates and studies, proposed
exploration and development of NorthWest’s exploration property
interests; the Company’s ability to finance future operations; the
potential size of a mineralized zone or potential expansion of
mineralization; geological interpretations; the estimation of
Mineral Resources; future operations; mine plans, and
magnitude or quality of mineral deposits.
All statements, other than statements of
historical fact, included herein, constitutes forward-looking
information. Although NorthWest believes that the expectations
reflected in such forward-looking information and/or information
are reasonable, undue reliance should not be placed on
forward-looking information since NorthWest can give no assurance
that such expectations will prove to be correct. Forward-looking
information involves known and unknown risks, uncertainties and
other factors that may cause actual results or events to differ
materially from those anticipated in such forward-looking
information, including the risks, uncertainties and other factors
identified in NorthWest’s periodic filings with Canadian securities
regulators. Forward-looking information are subject to business and
economic risks and uncertainties and other factors that could cause
actual results of operations to differ materially from those
contained in the forward-looking information. Important factors
that could cause actual results to differ materially from
NorthWest’s expectations include risks associated with the business
of NorthWest; risks related to reliance on technical information
provided by NorthWest; risks related to exploration and potential
development of the Company’s mineral properties; business and
economic conditions in the mining industry generally; fluctuations
in commodity prices and currency exchange rates; uncertainties
relating to interpretation of drill results and the geology,
continuity and grade of mineral deposits; the need for cooperation
of government agencies and First Nation groups in the exploration
and development of properties and the issuance of required permits;
the need to obtain additional financing to develop properties and
uncertainty as to the availability and terms of future financing;
the possibility of delay in exploration or development programs and
uncertainty of meeting anticipated program milestones; uncertainty
as to timely availability of permits and other governmental
approvals; and other risk factors as detailed from time to time and
additional risks identified in NorthWest’s filings with Canadian
securities regulators on SEDAR+ in Canada (available at
www.sedarplus.com).
Forward-looking information is based on
estimates and opinions of management at the date the information
are made. NorthWest does not undertake any obligation to update
forward-looking information except as required by applicable
securities laws. Investors should not place undue reliance on
forward-looking information.
A photo accompanying this announcement is available at
https://www.globenewswire.com/NewsRoom/AttachmentNg/298c73d4-eaeb-454b-b98c-c2cf853b046d
Northwest Copper (TSXV:NWST)
Historical Stock Chart
From Oct 2024 to Nov 2024
Northwest Copper (TSXV:NWST)
Historical Stock Chart
From Nov 2023 to Nov 2024