Marimaca Copper Corp. (“Marimaca Copper” or the
“Company”) (TSX: MARI) is pleased to
announce the results of the five drill hole diamond drilling
exploration program from the eastern margin of the Marimaca Oxide
Deposit (“MOD”). The program was designed to follow-up on the
sulphide-bearing intersection of the previously released hole
MAD-22, which intersected higher grades of primary copper
mineralization down-dip of the Marimaca oxides. The program
encountered challenging drilling conditions due to the orientation
of the drilling from existing drill-pads along major known
structures at the MOD. Results from this program and learnings
regarding the approach for potential future deeper drilling,
particularly origin and orientation, and will be considered for the
design of follow-up exploration work. A discussion of results is
provided in the “Geological Discussion” section of this news
release.
Highlights
- Four drill
holes recovered to a maximum depth of 349m from surface, with three
holes completed successfully to target depth
- The fourth
hole, although recovered, MAD-25 was terminated above target depth
due to poor rock quality caused by localized faulting
- Holes
MAD-24, 25, 26 and 27 intersected the extension of the upper oxide
and mixed/enriched copper mineralization
- This zone
is interpreted as the near-surface, oxidized expressions of
high-grade mineralized structures encountered in
MAD-22
- MAD-25
intersected 56m at 0.40% CuT from 136m including 24m at 0.63% CuT
of secondary and primary sulphides in-line with the projected
horizon from MAD-22, however, could not progress further into the
horizon due to rock quality in a fault zone and was terminated at
218m
- Hole MAD-24
intersected 74m of 0.52% CuT from 24m including 18m at 0.68% CuT
from 24m and 28m at 0.79% CuT from 64m above the projected sulphide
horizon
- Hole MAD-24
intersected a barren post-mineral dyke from 224.3m which occupied
the projected extension of the sulphide horizon from
MAD-22
- Hole MAD-27
intersected 40m at 0.50% CuT from 68m including 18m at 0.90% CuT of
mixed and enriched mineralization from 74m, and a deeper
intersection of 12m at 1.0% CuT of chalcopyrite mineralization from
162m
- Hole MAD-26
intersected strong magnetite alteration from 186m, however with a
higher pyrite/chalcopyrite ratio relative to MAD-22 corresponding
to lower grade copper intersections
- MAD-23 was
terminated as a result of contractor operational performance
leading to contractor replacement for subsequent holes (MAD-24, 25,
26, 27)
Sergio Rivera, VP Exploration of
Marimaca Copper, commented:
“Despite challenging drilling conditions we
continue to improve our understanding of Marimaca’s genesis and
target generation for the potential sulphide feeder zones. We are
very encouraged to see the continuation of the alteration
assemblages and rock types observed in MAD-22 in the follow-up
program, which is the first time that consistent
sulphide-associated alteration has been observed below the MOD.
MAD-25, in particular, which stepped out 500m to the south of
MAD-22, intersected the expected alteration mineral assemblages
with strong mineralization at the targeted horizon, but was
terminated before the expected higher-grade zone due to the
intersection of a fault zone, which deviated the hole.
Planning for the next phase of sulphide
exploration will incorporate learnings from this first phase
campaign, including adjusting the approach to drilling from east to
west to allow for easier orientation of the drilling to the deeper
target horizons. Approaching from the west will take time to plan
new drilling infrastructure rather than using existing eastern
drill pads at the MOD, however we believe the sulphide potential
warrants this.
We continue to believe that the sulphide
potential is high, particularly considering the scale of the
oxidized mineralized body at the MOD and the indications, such as
Hole MAD-22, that higher grade remnant feeder structures, remain
intact in the shallower down-dip zones of the MOD.”
Figure 1: Plan view of drill
holes
Figure 2: Idealized 3D view of MOD
(looking North) with interpreted sulphide feeder horizon and 2023
MRE pit
Figure 3: Idealized long and cross 3D
view of MOD with MAD-22 interpreted Chalcopyrite-dominated zones
identified
Further Drill Hole
Observations
- Hole MAD-25 was a
500m step out to the south of MAD-22 and intersected strong mixed
and primary sulphide mineralization from near the projected target
horizon, at approximately 136m downhole, but was terminated due to
fault intersection at 218m
- Holes MAD-25, 26
and 27 intersected extensions of similar alteration-mineralization
assemblages comparable with MAD-22 including sections showing
massive to stringer filling chalcopyrite and pyrite and pervasive
hydrothermal magnetite replacement, partially related to coarse
actinolite veinlets associated with the porphyritic quartz-diorite
intrusion host rock
- Located immediately
adjacent to the eastern wall of the whittle pit limits for the
October 2022 MRE, indicating potential for high grade, open
pit-able mineralization
- Sulphide copper
mineralization encountered in the deeper mineralized intercepts
were less consistent than MAD-22 due to variability in
pyrite/chalcopyrite ratio in the primary zones
- This variation is
common in IOCG systems, which further analysis required to vector
to the higher chalcopyrite-bearing zones
- This was observed
in MAD-26, which intersected strong magnetite alteration from 186m,
however with a higher pyrite/chalcopyrite ratio relative to MAD-22
corresponding to lower grade copper intersections
Geological Discussion
Results from MAD-22 and follow up sulphide
exploration drilling continue to support the current interpretation
of the mineralized system at the MOD. The large-scale nature of the
supergene (oxide) mineralized body at the MOD, and the alteration
assemblages and remnant primary sulphide-bearing structures
encountered in MAD-22, 25, 26 and 27 continue to provide strong
evidence for a sulphide-rich ‘feeder’ system which can be
interpreted as the source for Marimaca’s oxide ore body.
Chalcopyrite and pyrite-bearing mineralization encountered in
drilling post-dates pervasive magnetite-actinolite alternation
which is consistently found down-dip of the MOD and corresponds to
the magnetic-highs identified in the high-resolution mag-drone
surveys (see press release dated February 15, 2023).
The program’s goal of stepping out from MAD-22
was hindered by the drilling orientation which was east-biased,
causing interference from parallel dykes and late faults on
north-south trends and dipping to the east. Planning for future
potential deep sulphide drilling will focus on a western
orientation which will require preparation of new drilling
infrastructure rather than use of existing access roads and MOD
drill pads. Despite the challenging conditions, the results from
MAD-24, 25, 26 and 27 further confirm the IOCG-nature of the
broader Marimaca mineralizing system which is hosted by a
monzodiorite stock affected by a system of parallel faults and
fractures which control the emplacement of superimposed
mineralization-alteration events.
Borehole Teleview analysis of holes MAD-24, 25,
26 and 27 returned similar results to that of MAD-22 in that that
the dominant structures controlling in the altered and higher-grade
primary mineralization are oriented north-north-east dipping at 75
to 80 degrees to the east. This is in contrast to the general
structural sense of the MOD, where dominant structures are oriented
more north south and are more shallow dipping to the east. The
importance of dacitic dykes and the north-west trending regional
faults and structures is also noted for the confluence of these
important geological features and their proximity to higher grade
mineralization, both in the oxide and primary mineral zones.
The explored area for Marimaca sulphides remains
very limited and relatively shallow (<450m depth), with the
deeper extents of the Marimaca system remaining untested and the
oxide/secondary sulphide column consistently reaching depths of
400m+. As previously noted, the size of the surface expression and
volumetric scale of the MOD continue to support the thesis that the
genesis of the Marimaca oxides must relate to a strong, successive
tectonic-magmatic event which introduced copper-sulphide bearing
structures that underwent repetitive oxidation events above depths
of 500m.
Background – Marimaca Sulphide
Exploration
Based on previous drilling and results from hole
MAD-22, the Company developed an exploration model which was based
on a strong correlation between higher grade chalcopyrite
mineralization and high magnetic susceptibility, which was used to
vector for future deeper drilling campaigns. During the 2021
campaign, the deeper drilling, which was targeting deeper sulphide
potential, encountered additional oxide and secondary sulphides in
a zone now known as MAMIX (refer to announcement dated 5
May 2021). This extended the envelope of leachable copper
minerals by, in some cases, several hundred meters. This discovery
was a core component of the upgraded Mineral Resource Estimate
(“MRE”) released in October 2022 (refer to announcement
dated 13 October 2022), but left the sulphide potential
unaddressed.
A review of historical drilling data highlighted
numerous broad zones of, typically remnant, primary mineralization,
especially around the centre of the project, which were identified
but never properly followed up on due the focus on the MAMIX Zone.
MAD-22 (a geotechnical hole testing rock quality on the eastern MOD
pit wall) was drilled on section N7,435,550, which is located 250m
to the south of N7,435,800 (Figure 1) and
intersected very high-grade primary copper mineralization. MAD-22
was drilled directly into an area with some of the highest magnetic
susceptibilities encountered at the project. As noted in the
release in December 2022, MAD-22 encountered very high grades of
primary copper mineralization over broad downhole widths and
encountered mineral textures of magnetite-actinolite veins and
stringers and massive chalcopyrite.
Table 1. Summary of Significant
Intercepts
Hole |
Depth (m) |
|
From (m) |
To (m) |
Intercept (m) |
%CuT |
MAD-23 |
No Recovery |
|
|
|
|
|
MAD-24 |
336 |
|
0 |
152 |
152 |
0.31 |
including |
24 |
122 |
98 |
0.43 |
including |
24 |
98 |
74 |
0.52 |
including |
24 |
42 |
18 |
0.68 |
and |
64 |
92 |
28 |
0.79 |
MAD-25 |
217.65 |
|
136 |
192 |
56 |
0.40 |
including |
164 |
188 |
24 |
0.63 |
MAD-26 |
348.9 |
|
154 |
268 |
114 |
0.19 |
including |
186 |
268 |
82 |
0.22 |
including |
190 |
230 |
40 |
0.31 |
including |
190 |
204 |
14 |
0.49 |
and |
212 |
230 |
18 |
0.28 |
and |
250 |
262 |
12 |
0.30 |
MAD-27 |
317.45 |
|
68 |
232 |
164 |
0.28 |
including |
162 |
232 |
70 |
0.32 |
including |
68 |
108 |
40 |
0.50 |
including |
74 |
92 |
18 |
0.90 |
and |
162 |
174 |
12 |
1.01 |
and |
192 |
206 |
14 |
0.33 |
and |
220 |
232 |
12 |
0.38 |
Table 2. Drill Collars and
Survey
Hole |
Easting |
Northing |
Elevation |
Azimuth |
Inclination |
Depth (m) |
MAD-23 |
- |
- |
- |
- |
- |
No Recovery |
MAD-24 |
375143.6 |
7435535.1 |
1125.0 |
90 |
-65 |
336.00 |
MAD-25 |
375204.2 |
7435426.3 |
1108.3 |
90 |
-65 |
217.65 |
MAD-26 |
375202.7 |
7435431.3 |
1108.1 |
40 |
-60 |
348.90 |
MAD-27 |
375143.5 |
7435537.1 |
1125.0 |
70 |
-55 |
317.45 |
Sampling and Assay Protocol
True widths cannot be determined with the
information available at this time. DDH holes were sampled on a 2m
continuous basis, halved by a conventional core splitter on site
with one half sent to the Andes Analytical Assay preparation
laboratory in Calama and the pulps then sent to the same company
laboratory in Santiago for assaying. Samples were prepared using
the following standard protocol: drying; crushing all sample to
-1/4” and passing through a secondary crusher to better than 80%
passing -10#; homogenizing; splitting; pulverizing a 400-600g
subsample to 95% passing -150#; and a 125g split of this sent for
assaying. All samples were assayed for %CuT (total copper); %CuS
(acid soluble copper) and Ag AAS. Au was Fire Assayed. A full QA/QC
program, involving insertion of appropriate blanks, standards and
duplicates was employed with acceptable results. Pulps and sample
rejects are stored by Marimaca Copper for future reference.
Qualified Person
The technical information in this news release,
including the information that relates to geology, drilling and
mineralization was prepared under the supervision of, or has been
reviewed by Sergio Rivera, VP of Exploration, Marimaca Copper Corp,
a geologist with more than 35 years of experience and a registered
member of the Comision Minera (Chilean Mining Commission), as well
a member of the Colegio de Geólogos de Chile, Instituto de
Ingenieros de Minas de Chile and of the Society of Economic
Geologist USA, and who is the Qualified Person for the purposes of
NI 43-101 responsible for the design and execution of the drilling
program.
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 Baynesmarimaca@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, uncertainties relating to regulatory
procedure and timing for permitting reviews, 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 27, 2023 and other filings made by the Company with the
Canadian securities regulatory authorities (which may be viewed
at www.sedar.com). 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 TSX nor the Canadian Investment
Regulatory Organization accepts responsibility for the adequacy or
accuracy of this release.
Figures accompanying this announcement are
available at
https://www.globenewswire.com/NewsRoom/AttachmentNg/37cf26ca-9ff4-4fb8-ac58-a3fa6b11b774
https://www.globenewswire.com/NewsRoom/AttachmentNg/e3db89f4-a47f-48f3-a849-4e0ff0e84f01
https://www.globenewswire.com/NewsRoom/AttachmentNg/27034ebe-6a79-430b-b653-6af1c0c85b04
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