Marimaca Announces Significant Increase in Mineral Resources at the Marimaca Copper Project 98% increase in M&I Resource tonnes to 140Mt at 0.48% CuT for 665.5kt of Contained Copper 92% growth in Inferred Resource tonnes to 83Mt at 0.39% CuT for 322.9kt of Contained Copper
News Release
Marimaca Announces Significant Increase in Mineral Resources at the Marimaca Copper
Project
98% increase in M&I Resource tonnes to 140Mt at 0.48% CuT for 665.5kt of Contained Copper
92% growth in Inferred Resource tonnes to 83Mt at 0.39% CuT for 322.9kt of Contained Copper
Marimaca Confirmed as One of the Largest Copper Discoveries in the Last Decade(2)
Vancouver, British Columbia, October 13, 2022 – 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
o 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
o 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
o 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
o 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
o Low pre‐strip and LOM strip ratio drive significant cost advantages
Clear opportunities remain for additional resource expansion with further exploration:
o Mineralization at the MOD remains open to the east, south‐east, and down‐plunge
o 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)
1 2019 MRE at a 0.22% cut‐off grade, 2022 MRE at a 0.15% cut‐off grade
2 Source: S&P Global Market Intelligence
3 Per the June 2020 PEA mine plan
Significant amount of remaining 2022 drilling to be captured in planned early 2023 MRE
o Targeting majority of tonnes to be captured in M&I categories to support eventual reserves
o 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
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 – Tonnage
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 Shell
Figure 3. Block Model Plan View – 2022 MRE
Figure 4. Plan View of Marimaca Satellite Exploration Targets
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