Marimaca Copper Corp. (“Marimaca Copper” or the
“Company”) (TSX: MARI) is pleased to
announce an updated Mineral Resource Estimate (“MRE”) for the
Marimaca Oxide Deposit (the “MOD” or the “Project”) located in the
Antofagasta region of northern Chile. The 2022 MRE demonstrates
significant resource growth over the 2019 MRE and marks an
important step-change in the scale of the Project, supporting a
potential production rate higher than proposed in the Preliminary
Economic Assessment (“PEA”).
The 2022 MRE incorporates 19,580m of ~41,500m of
drilling (reverse circulation (“RC”) + diamond) completed in 2022
for a total of over 110,000m of drilling completed since 2016. The
balance of the 2022 infill drilling program, totalling
approximately 28,000m, will be included in a subsequent MRE planned
for early 2023 with the objective of converting the remaining
Inferred Resources to the Measured and Indicated Categories to
underpin the Definitive Feasibility Study (“DFS”) planned for
2023.
The 2022 MRE was prepared in accordance with the
Canadian Institute of Mining, Metallurgy and Petroleum ("CIM")
Definition Standards and National Instrument 43-101 - Standards of
Disclosure for Mineral Projects ("NI 43-101").
Highlights
- Significant
increase in M&I and Inferred tonnage and contained metal over
the 2019 MRE1
- 98% growth
in Measured and Indicated Resource tonnage to 139.6Mt at 0.48% CuT
(0.30% CuS) for ~665,000 tonnes of contained Cu metal
- 92% growth
in Inferred Resource tonnage to 82.7Mt at 0.39% CuT (0.16% CuS) for
~323,000 tonnes of contained Cu
- Establishes
Marimaca as one of the largest copper discoveries globally in the
last decade2 and has positive
implications for production scale increases in future development
studies
- 50kt and
60kt per annum copper cathode production cases (vs. 36ktpa LOM
average in PEA) will be assessed for DFS
- High grade
core which comprises the first six years of the 2019 PEA mine life
is expected to remain intact and accessible in a scaled-up
development scenario
-
Approximately 50Mt at 0.7% CuT commencing from surface in
green oxide3 for ~350,000 tonnes
of contained metal
- Very low
strip ratio of 1:1 maintained in constraining pit shell, with all
resources captured in a single continuous pit
- Low
pre-strip and LOM strip ratio drive significant cost
advantages
- Clear
opportunities remain for additional resource expansion with further
exploration:
-
Mineralization at the MOD remains open to the east,
south-east, and down-plunge
- Near mine
(<5km) satellite targets discovered in 2021 – Mercedes, Cindy,
and Robles (see announcement dated January 20, 2022) – provide high
probability targets for further mine life extension
- 2019 MRE
showed relatively low sensitivity to changes in underlying copper
price assumption indicating high return on investment of 2021 and
2022 drilling campaigns as they pertained to resource growth for
the MOD (see Figure 1)
- Significant
amount of remaining 2022 drilling to be captured in planned early
2023 MRE
- Targeting
majority of tonnes to be captured in M&I categories to support
eventual reserves
- Potential
for new higher-grade green oxide zone identified in the shallow
north and north- eastern areas of MOD to have positive grade
implications for final MRE in early 2023
1 2019 MRE at a 0.22% cut-off grade, 2022 MRE at
a 0.15% cut-off grade2 Source: S&P Global Market Intelligence3
Per the June 2020 PEA mine plan
Hayden Locke, President & CEO of
Marimaca Copper, commented:
“Sergio Rivera and his team delivered two very
successful drilling programs in 2021 and 2022 through challenging
operating conditions discovering new additional mineralisation
adjacent and below the current Marimaca pit model. The 2022 MRE is
a fantastic achievement and reflects the exceptional exploration
and geological work completed by our extremely dedicated team.
“With the discovery of the MOD depth extensions
in 2021, we believed there was the potential to make a step change
in the scale of the resource. This MRE has clearly achieved that.
It establishes the MOD as one of the most significant greenfield
copper oxide discoveries in the last 20 years and confirms its
potential to host over one million tonnes of contained copper in a
single pit.
“Given the M&I resource estimate already
points to more than 600,000 tonnes of contained metal, the Project
will now clearly support a larger operation in terms of copper
cathode production, but also a meaningful mine life extension. We
will assess production scenarios between 50,000 and 60,000 tonnes
per annum prior to commencing our Definitive Feasibility Study in
2023.
“Importantly, the positive attributes which were
key to the MOD’s industry leading return on invested capital (ROIC)
metrics – low life of mine strip ratio, shallow high-grade core in
the first five years of the mine life, minimal pre-strip and low
expected start up capital cost – remain firmly intact, meaning this
resource upgrade will be reflected as a material improvement in
project value.
“We have completed another 28,000m of drilling
for which we are waiting on results. These will be released over
the coming months and incorporated into a final MRE in early 2023,
which will form the basis of our development plans for the
Project.”
Summary of 2022 Mineral Resource
Estimate
The 2022 MRE was completed by independent
consultants NCL Ingeniería y Construcción SpA (“NCL”) and verified
by Luis Oviedo of NCL, a qualified person under NI 43-101 and
independent of Marimaca. The 2022 MRE incorporates 110,790m of
drilling across 424 drill holes completed between 2016 and 2022 and
is reported with an effective date of October 13, 2022. The Whittle
Optimisations were run using the operating cost parameters from the
Preliminary Economic Assessment for the Project and US$4/lb copper
price assumption.
Mineral Resource Category and Type |
Quantity |
CuT |
CuS |
CuT |
CuS |
(kt) |
(%) |
(%) |
(t) |
(t) |
Total Measured |
47,051 |
0.54 |
0.36 |
253,157 |
167,614 |
Total Indicated |
92,516 |
0.45 |
0.26 |
412,375 |
244,200 |
Total Measured and Indicated |
139,567 |
0.48 |
0.30 |
665,531 |
411,814 |
Total Inferred |
82,678 |
0.39 |
0.16 |
322,910 |
128,416 |
Table 1. 2022 Mineral Resource
Estimate
* Pit shell constrained resources with demonstrated
reasonable prospects for eventual economic extraction (RPEEE) are
generated using series of Lerchs-Grossmann pit shell optimizations
completed by NCL* CuT means total copper and CuS means acid soluble
copper. Technical and economic parameters include: copper price
US$4.00/lb; mining cost US$1.51/t; HL processing cost US$5.94/t
(incl. G&A); ROM processing cost US$1.65/t (incl. G&A);
selling cost US$0.16/lb Cu; heap leach recovery 76% of CuT; ROM
recovery 40% of CuT; and 45°-52° pit slope angle* With the economic
parameters stated above, the Cut-Off grade of the Mineral Resource
Estimate is approximately 0.15% CuT and a strip ratio of 1:1 has
been estimated by NCL.* Mineral resources which are not mineral
reserves do not have demonstrated economic viability. Due to the
uncertainty which may attach to inferred mineral resources, it
cannot be assumed that all or any part of an inferred mineral
resource will be upgraded to an indicated or measured mineral
resource as a result of continued exploration
Cut-off grade (% CuT) |
Measured |
Indicated |
Measured + Indicated |
Inferred |
|
|
Quantity kt |
CuT [%] |
CuS [%] |
Quantity kt |
CuT [%] |
CuS [%] |
Quantity kt |
CuT [%] |
CuS [%] |
Quantity kt |
CuT [%] |
CuS [%] |
|
0.40 |
24,607 |
0.79 |
0.53 |
37,550 |
0.72 |
0.44 |
62,158 |
0.74 |
0.48 |
27,222 |
0.68 |
0.25 |
|
0.30 |
32,157 |
0.68 |
0.46 |
54,563 |
0.60 |
0.37 |
86,720 |
0.63 |
0.40 |
41,422 |
0.56 |
0.22 |
|
0.25 |
36,837 |
0.63 |
0.42 |
65,910 |
0.55 |
0.33 |
102,746 |
0.58 |
0.36 |
52,332 |
0.50 |
0.20 |
|
0.22 |
40,000 |
0.60 |
0.40 |
73,517 |
0.51 |
0.31 |
113,517 |
0.54 |
0.34 |
60,431 |
0.47 |
0.19 |
|
0.20 |
42,206 |
0.58 |
0.39 |
78,880 |
0.49 |
0.30 |
121,086 |
0.52 |
0.33 |
66,256 |
0.44 |
0.18 |
|
0.18 |
44,291 |
0.56 |
0.37 |
84,610 |
0.47 |
0.28 |
128,900 |
0.50 |
0.31 |
72,670 |
0.42 |
0.17 |
|
0.15 |
47,051 |
0.54 |
0.36 |
92,516 |
0.45 |
0.26 |
139,567 |
0.48 |
0.30 |
82,678 |
0.39 |
0.16 |
|
0.10 |
50,536 |
0.51 |
0.34 |
100,946 |
0.42 |
0.25 |
151,482 |
0.45 |
0.28 |
96,064 |
0.35 |
0.14 |
|
0.05 |
57,125 |
0.46 |
0.30 |
119,653 |
0.36 |
0.21 |
176,777 |
0.39 |
0.24 |
123,552 |
0.29 |
0.11 |
|
0.00 |
61,333 |
0.43 |
0.28 |
129,985 |
0.34 |
0.20 |
191,318 |
0.37 |
0.22 |
134,056 |
0.27 |
0.11 |
|
Table 2. Mineral Resource
Sensitivity
* Pit shell constrained resources with demonstrated
reasonable prospects for eventual economic extraction (RPEEE) are
generated using series of Lerchs-Grossmann pit shell optimizations
completed by NCL* CuT means total copper and CuS means acid soluble
copper. Technical and economic parameters include: copper price
US$4.00/lb; mining cost US$1.51/t; HL processing cost US$5.94/t
(incl. G&A); ROM processing cost US$1.65/t (incl. G&A);
selling cost US$0.16/lb Cu; heap leach recovery 76% of CuT; ROM
recovery 40% of CuT; and 45°-52° pit slope angle* With the economic
parameters stated above, the Cut-Off grade of the Mineral Resource
Estimate is approximately 0.15% CuT and a strip ratio of 1:1 has
been estimated by NCL.* Mineral resources which are not mineral
reserves do not have demonstrated economic viability. Due to the
uncertainty which may attach to inferred mineral resources, it
cannot be assumed that all or any part of an inferred mineral
resource will be upgraded to an indicated or measured mineral
resource as a result of continued exploration
Outcome of 2021 and 2022 Expansion &
Infill Drill Programs
Figure 1 demonstrates Resource growth in the
2022 MRE attributable to both the increased copper price
assumption, and growth driven by the results of the 2021 and 2022
drilling campaigns. Drilling delivered strong extensions both below
the previously interpreted limits of the Marimaca oxide
mineralization into the newly-discovered zone of mixed
mineralization (“MAMIX”), as well as on the east and south-east
periphery of the MOD where mineralization was previously
interpreted to be thinning. Both areas delivered extensions to
higher-grade zones and had a positive influence on the contained
metal increases in the 2022 MRE relative to the 2019 MRE.
Figure 1. Resource Growth –
Tonnagehttps://www.globenewswire.com/NewsRoom/AttachmentNg/51043c14-d8d9-47a5-be47-9e052c09dcab
Metallurgy Commentary
Marimaca has completed 5 phases of extensive
metallurgical test work at Marimaca. Results from Phase 5 were
announced on June 15, 2022 following a rigorous program including
full-scale column testing, mini-column testing, container-leach
testing, sulfation tests, acid sensitivity testing, Iso-pH testing,
and head characterization for heap leach (“HL”) and run-of-mine
(“ROM”) samples. In-line with results from Phases 1-4, Phase 5
recoveries in the column and bottle roll tests generally exceeded
the solubility ratio (CuS/CuT) and leaching potential of the
samples, indicating a potentially larger proportion of total copper
will be recovered in industrial-scale operations. The leaching
potential of copper ores is defined as acid soluble copper (CuS)
plus cyanide soluble copper (CuCN) divided by total copper (CuT).
The acid solubility ratio (CuS/CuT) for copper oxides such as
atacamite, brochantite and chrysocolla, which dissolve quickly when
exposed to acid, is a good predictor of leachability. However,
where the mineralization has several copper bearing minerals with
different dissolution characteristics under these leaching
conditions (such as Marimaca’s black oxide (wad) component), the
copper acid solubility ratio may materially underestimate the acid
leaching potential for heap leach operations, especially where
soluble copper sulphides such as chalcocite, covellite and bornite
are present.
The Marimaca Deposit
Commentary
The 2021/22 drilling programs and subsequent
2022 MRE provide further validation of the Marimaca geological
model developed by the Company’s exploration team. Figure 2 (long
section) demonstrates the continuity of the oxide mineralization
across the N-S extent of the deposit. Mineralization is hosted
consistently by east-dipping fracture sets with higher grades
concentrated along controlling NW-SE structures and splays. Higher
grade green oxide mineralization (brochantite, atacamite,
chrysocolla) dominates the core of the deposit and is located
near-surface. High grade zones of oxides, mixed and enriched
mineralization extend at depth into the underlying MAMIX zone which
was an important driver of growth in the 2022 MRE. Due to the
continuous nature of mineralization, the increased copper price
assumption does not materially impact the Project’s strip ratio due
to the extensive green and black oxide (wad) mineralized halo which
gets captured by the larger resource pit.
The Company believes that significant oxide
resource upside remains at the MOD and in nearby satellite targets.
At the MOD, mineralized intercepts located to the east and
southeast of the deposit have not been captured in the 2022 MRE due
to lack of sufficient drill density. The MOD remains open to the
east and southeast and further exploration may be planned in due
course. In addition, the satellite oxide discoveries made in 2021
(Mercedes, Cindy, Roble) have not received sufficient drilling to
be included in the 2022 MRE. The plan map seen in Figure 4
demonstrates the proximity of the satellite targets to the 2022 MRE
resource pit.
Figure 2. Long Section, Looking North-East,
2022 MRE Pit
Shellhttps://www.globenewswire.com/NewsRoom/AttachmentNg/97facfaf-c411-44aa-849a-4999346486ff
Figure 3. Block Model Plan View – 2022
MREhttps://www.globenewswire.com/NewsRoom/AttachmentNg/08428edb-1051-4fca-a400-23e70e092445
Figure 4. Plan View of Marimaca Satellite
Exploration
Targetshttps://www.globenewswire.com/NewsRoom/AttachmentNg/ddd27096-27c1-4ec3-a64e-4183e3afd6e6
The potential quantity and grade
presented in the exploration target ranges are conceptual and have
insufficient exploration and drill density to define a Mineral
Resource. At this stage, it is uncertain if further exploration
will result in the targets being delineated as a Mineral Resource.
Estimates of exploration targets are not Mineral Resources and are
too speculative to meet the NI 43-101 reporting standards. The
detailed methodology for preparing the Exploration Targets and a
summary of supporting technical data can be found in the
announcement dated January 20, 2022 “Marimaca Announces Exploration
Targets for Near-Pit Oxide Satellites and MAMIX Depth
Extension”.
2022 MRE Estimation
Parameters
Grade estimates were completed using ordinary
kriging with nominal block size measuring 5m by 5m by 5m. Resources
have been classified by their proximity to sample locations and
number of drill holes and samples within different search
ellipsoids, and are reported according to Canadian Institute of
Mining, Metallurgy and Petroleum (CIM) Definition Standards for
Mineral Resources and Mineral Reserves and National Instrument
43-101 - Standards of Disclosure for Mineral Projects.
Operating costs and certain operating
parameters, such as metallurgical recoveries, were taken from the
2020 Preliminary Economic Assessment, which was completed by
Ausenco according to Canadian Institute of Mining, Metallurgy and
Petroleum (CIM) Definition Standards for Mineral Resources and
Mineral Reserves and National Instrument 43-101 - Standards of
Disclosure for Mineral Projects.
Mineral Resource Category and Type |
Quantity |
CuT |
CuS |
CuT |
CuS |
(kt) |
(%) |
(%) |
(t) |
(t) |
Measured |
|
|
|
|
|
Brochantite |
22,371 |
0.65 |
0.47 |
144,870 |
104,957 |
Chrysocolla |
12,252 |
0.46 |
0.36 |
56,558 |
44,057 |
Wad/Black oxides |
6,578 |
0.31 |
0.17 |
20,366 |
11,445 |
Mixed |
5,106 |
0.55 |
0.13 |
28,176 |
6,693 |
Enriched |
743 |
0.43 |
0.06 |
3,186 |
462 |
Total Measured |
47,051 |
0.54 |
0.36 |
253,157 |
167,614 |
Indicated |
|
|
|
|
|
Brochantite |
27,865 |
0.60 |
0.44 |
166,469 |
122,706 |
Chrysocolla |
18,239 |
0.41 |
0.30 |
74,012 |
55,497 |
Wad/Black oxides |
28,036 |
0.29 |
0.16 |
82,607 |
45,340 |
Mixed |
14,557 |
0.51 |
0.13 |
73,595 |
18,413 |
Enriched |
3,819 |
0.41 |
0.06 |
15,692 |
2,244 |
Total Indicated |
92,516 |
0.45 |
0.26 |
412,375 |
244,200 |
Measured and Indicated |
|
|
|
|
|
Brochantite |
50,235 |
0.62 |
0.45 |
311,340 |
227,663 |
Chrysocolla |
30,492 |
0.43 |
0.33 |
130,571 |
99,554 |
Wad/Black oxides |
34,614 |
0.30 |
0.16 |
102,973 |
56,785 |
Mixed |
19,664 |
0.52 |
0.13 |
101,771 |
25,106 |
Enriched |
4,562 |
0.41 |
0.06 |
18,877 |
2,706 |
Total Measured and Indicated |
139,567 |
0.48 |
0.30 |
665,531 |
411,814 |
Inferred |
|
|
|
|
|
Brochantite |
10,364 |
0.52 |
0.37 |
54,026 |
38,124 |
Chrysocolla |
9,028 |
0.35 |
0.25 |
31,400 |
22,496 |
Wad/Black oxides |
24,907 |
0.28 |
0.14 |
70,325 |
35,229 |
Mixed |
17,129 |
0.47 |
0.12 |
80,152 |
19,809 |
Enriched |
21,249 |
0.41 |
0.06 |
87,008 |
12,758 |
Total Inferred |
82,678 |
0.39 |
0.16 |
322,910 |
128,416 |
Table 3. 2022 MRE by Mineralization
Type
* Pit shell constrained resources with demonstrated
reasonable prospects for eventual economic extraction (RPEEE) are
generated using series of Lerchs-Grossmann pit shell optimizations
completed by NCL* CuT means total copper and CuS means acid soluble
copper. Technical and economic parameters include: copper price
US$4.00/lb; mining cost US$1.51/t; HL processing cost US$5.94/t
(incl. G&A); ROM processing cost US$1.65/t (incl. G&A);
selling cost US$0.16/lb Cu; heap leach recovery 76% of CuT; ROM
recovery 40% of CuT; and 45°-52° pit slope angle* With the economic
parameters stated above, the Cut-Off grade of the Mineral Resource
Estimate is approximately 0.15% CuT and a strip ratio of 1:1 has
been estimated by NCL.* Mineral resources which are not mineral
reserves do not have demonstrated economic viability. Due to the
uncertainty which may attach to inferred mineral resources, it
cannot be assumed that all or any part of an inferred mineral
resource will be upgraded to an indicated or measured mineral
resource as a result of continued exploration
Qualified Person
The technical information in this news release,
including the information related to geology, drilling,
mineralization, modeling and estimation has been reviewed and
approved by Luis Oviedo, an independent Consulting Geologist with
more than 45 years of experience. Mr. Oviedo is a member of the
Colegio de Geólogos and the Institute of Mining Engineers of Chile
and is an Independent Qualified Person as defined by National
Instrument 43-101 – Standards of Disclosure for Mineral
Projects.
The QP confirms he has visited the project area,
has reviewed relevant project information, is responsible for the
information contained in this news release, and consents to its
publication.
Contact InformationFor further
information please visit www.marimaca.com or contact:
Tavistock +44 (0) 207 920
3150Emily Moss / Adam Baynes
marimaca@tavistock.co.uk
Forward Looking Statements
This news release includes certain
“forward-looking statements” under applicable Canadian securities
legislation. There can be no assurance that such statements will
prove to be accurate, and actual results and future events could
differ materially from those anticipated in such statements.
Forward-looking statements reflect the beliefs, opinions and
projections on the date the statements are made and are based upon
a number of assumptions and estimates that, while considered
reasonable by Marimaca Copper, are inherently subject to
significant business, economic, competitive, political and social
uncertainties and contingencies. Many factors, both known and
unknown, could cause actual results, performance or achievements to
be materially different from the results, performance or
achievements that are or may be expressed or implied by such
forward-looking statements and the parties have made assumptions
and estimates based on or related to many of these factors. Such
factors include, without limitation: risks related to share price
and market conditions, the inherent risks involved in the mining,
exploration and development of mineral properties, the
uncertainties involved in interpreting drilling results and other
geological data, fluctuating metal prices, the possibility of
project delays or cost overruns or unanticipated excessive
operating costs and expenses, uncertainties related to the
necessity of financing, the availability of and costs of financing
needed in the future as well as those factors disclosed in the
annual information form of the Company dated March 28, 2022, the
final short form base prospectus and other filings made by the
Company with the Canadian securities regulatory authorities (which
may be viewed at www.sedar.com). Accordingly, readers should
not place undue reliance on forward-looking statements. Marimaca
Copper undertakes no obligation to update publicly or otherwise
revise any forward-looking statements contained herein whether as a
result of new information or future events or otherwise, except as
may be required by law.
Neither the Toronto Stock Exchange nor the
Investment Industry Regulatory Organization of Canada accepts
responsibility for the adequacy or accuracy of this
release.
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