Marimaca Copper Corp. (“Marimaca Copper” or the
“Company”) (TSX: MARI) is pleased to
announce the results of the phase 4 metallurgical testing program
(“the Program”) for the Company’s flagship Marimaca Copper Project
(“Marimaca” or “the Project”), located in northern Chile.
The results confirm the recovery assumptions made
in the recently released PEA (refer to announcement on 4
August 2020), which projected Marimaca to have industry
leading pre-production capital costs and bottom quartile all in
sustaining cash costs, delivering compelling economics including a
post tax NPV8 of US$524m and an IRR of
33.5% at a US$3.15/lb copper price.
Highlights
- Comprehensive metallurgical testing program completed
comprising composite samples from all defined mineral sub-zones at
Marimaca
- Builds upon results from Phases 1,2 and 3 testing and
broadened sampling across the deposit
- Provides a comprehensive assessment of variability
across the deposit
- Testing covered multiple items including mini-columns
and 1.5m columns to give strong indication of eventual heap leach
recoveries
- Results confirm the recovery assumptions made in the
PEA
- Average life of mine recovery estimated to be 75.7% of
total copper for heap leach and 40% for dump leach
- Recoveries exceeded acid soluble component of total
copper in virtually all samples, some by significant margins,
indicating a larger proportion of the copper is acid soluble and
will be recovered in heap leaching
- Seawater confirmed to be compatible with heap leaching
process with no reduction in recovery and some increases in
recovery noted in certain mineral sub-zones
- Multiple areas identified for optimization work to
further improve economics of Marimaca
- Phase 5 program planned to address final metallurgical
aspects ahead of a Preliminary Feasibility Study and optimize
operating parameters for the Project
Luis Tondo, CEO of Marimaca Copper
commented:
“We are extremely pleased with the results of the
Phase 4 metallurgical program, which confirm the important
assumptions we have made in the PEA with respect to copper recovery
at Marimaca. As in the first three phases, recoveries exceeded acid
solubility ratios for virtually all samples. It was a particularly
positive surprise that, in several cases, the recoveries exceeded
the calculated maximum expected recovery (leaching potential) of
the sample material. This is attributed to the presence of black
copper oxide species, which have strong leaching profiles but did
not report to the soluble copper assays. This provides us with a
high level of confidence in our ability to achieve the recovery
assumptions applied in the PEA.
“This is a significant de-risking milestone as we
continue to move Marimaca towards future development and we are now
planning for the next phase of studies, which we hope to commence
before the end of 2020. In addition, we are continuing with our
extensive exploration program to test the exciting potential in the
Marimaca district.”
Figure 1: Plan Showing Location of Drilling
Samples Used in Marimaca Geomet Test Work Programs Phases 1 to
4: https://www.globenewswire.com/NewsRoom/AttachmentNg/d7dbb5ca-7280-461d-9898-ee9f502dbdb4
Overview of Metallurgical Test Work
Programs Completed
METALLURGICAL TESTING PHASE 4
The Phase 4 metallurgical test work program, which
commenced in September 2019, builds upon the results received in
Phases 1, 2 and 3 testing programs. This phase was designed to be
broader in its coverage of the metallurgical response of Marimaca,
providing significantly more detail with respect to certain
mineralisation sub zones and addressing some aspects of variability
across the deposit.
Phase 4 was designed and executed under the
supervision of Marcelo Jo of Jo & Loyola Process Consultants,
who has 35 years’ experience in processing, and supported by
Randolph E. Scheffel, a Consultant Metallurgical Engineer with over
45 years’ experience in copper processing.
Composite samples were taken from the following
updated mineral subzones:
- Brochantite / Atacamite;
- Chrysocolla;
- Copper Wad;
- Mixed; and
- Enriched.
Each zone has different copper mineral species and,
it was noted in the tests conducted in the Phase 3 program, the
overall leaching recovery exceeded the acid solubility ratio across
the samples. Assessing the leaching characteristics of each
subzone, and their true leaching potential, is an important step in
developing a robust geo-metallurgical model, which considers
variability across the deposit and provides data to optimize future
design.
Tests undertaken in Phase 4 included:
- Head grade characterization, with sequential copper
analysis
- Particle size characterization
- Sulphation test
- 1.5 iso-pH test, with and without seawater
- Acid and chloride leaching tests in 30cm mini-columns
- 1.5m columns tests
- ROM leaching in 1m3 iso containers of a low-grade wad sample
with minor presence of chrysocolla, atacamite and secondary
sulphides.
PHASE 4 METALLURGICAL TESTING
RESULTS
Mini-Column Testing
Material from 15 composite samples, taken from
across the Marimaca deposit, were subjected to 30cm column leach
tests to identify total recovered copper and total acid
consumption. Several different testing parameters were used,
including agglomerating with and without NaCl. The results were
very favorable, indicating strong recoveries and relatively fast
leach kinetics across all samples, relative to the acid soluble
copper ratios for the samples. Virtually all samples recoveries
exceeded the acid solubility ratios, in the case of the Mixed
mineral sub-zone, quite materially.
Of note, numerous samples from the brochantite,
chrysocolla and copper wad zones observed total copper recoveries
in excess of the calculated leaching potential of the samples. This
is due to black oxides in these zones, which are acid soluble but
have slower leach kinetics and, therefore, are not detected in the
acid soluble copper test.
Figure 2: Summary of Total Copper
Recoveries Vs Acid Soluble Copper Vs Leaching Potential in 0.3m
Column
Tests: https://www.globenewswire.com/NewsRoom/AttachmentNg/90ddb888-ca24-465b-85b7-e84146ea2d4e
1.5m Column Testing
Testing was completed on three composite samples
taken from a variety of areas across the Marimaca deposit. A total
of four 1.5m columns were completed. For Oxide and Combined
samples, no additional NaCl was added; for the Combined and
Sulphide materials, NaCl was added during agglomeration at a ratio
of 15 kg/ton.
Again, the results were favorable, with relatively
fast leach kinetics and three of the four columns achieving total
copper recoveries in excess of 70% within 60 days. One sample,
which comprised primarily oxides, which are the dominant copper
bearing mineral species in the deposit, reached recoveries in
excess of 80% within approximately 40 days.
Figure 3: Copper Recovery and Acid
Consumption Curves in 1.5m Column
Tests: https://www.globenewswire.com/NewsRoom/AttachmentNg/20e596ac-647b-4902-a339-18c02a7f3dbe
It was noted that there is a linear relationship
between time and acid consumption, and that a higher leach pad
height produced a lower specific acid consumption while still
achieving the recovery rates observed in the testing program. This
should allow further optimization of design to lower overall acid
recoveries. In the PEA, a trade-off study was completed to select a
4m heap height design. The copper dissolution and acid consumption
kinetics were modelled using METSIM software in order to project
and scale-up laboratory results and generate and economic
evaluation in each case, which was then used to determine the
optimum design parameters.
METALLURGICAL TEST WORK PHASES
The Company has now completed four phases of
metallurgical test work between April 2017 and August 2020. A fifth
phase, which extends the previous programs, will commence in the
third quarter of 2020. The results of Phases 1, 2 and 3 were
included in the NI43-101 Definitive Feasibility Study for Marimaca
1-23, released on 29 June 2018.
These tests were carried out by Geomet S.A., a well
known, ISO 9001 certified, Chilean laboratory with considerable
experience in metallurgical programs for copper deposits in
Chile.
These tests were completed on materials obtained
from Marimaca to characterise the metallurgical response of the
deposit to different operational conditions. The first three phases
were performed on a variety of parameters including agglomeration
conditions, granulometry, column height, irrigation rates and acid
consumption. These tests were followed up with more detailed
analysis including bottle roll iso-pH tests.
The overall metallurgical recovery of 65% of total
copper estimated for the 2018 DFS was improved approximately 76% of
total copper, based on the results of the Phase 4 program.
A fifth phase will be undertaken to refine any
remaining areas of potential risk or opportunities of the Project.
This will likely include optimisation of both acid consumption and
recoveries, as well as addressing variability across the deposit,
and providing information for the completion of a Pre-Feasibility
or Feasibility Study. Among the various conditions that will be
studied are; feed particle size, leaching conditions, acid
concentration and leaching solution distribution strategy.
Qualified Person
The Qualified Person for technical information in
this news release is Marcelo Jo, General Manager of Jo y Loyola
Process Consulting, a chemical engineer with more than 35 years of
experience and a Fellow of Chilean Mining Engineers Institute.
Metallurgical Qualified Person according the Chilean Mining
Committee for the purposes of NI 43-101.
The Qualified Person for content other than
metallurgical information in this news release is Luis Tondo, Chief
Executive Officer and Director of Marimaca Copper, a mining
engineer with more than 30 years of experience and a Fellow of The
Australasian Institute of Mining and Metallurgy, who is the
Qualified Person for the purposes of NI 43-101.
Both QPs confirm they have visited the project
area, have reviewed relevant project information, are responsible
for the information contained in this news release, and consent to
its publication.
Contact InformationFor further
information please visit www.marimaca.com or contact:
Tavistock +44 (0) 207 920
3150Jos Simson/Emily Mossmarimaca@tavistock.co.uk
Forward Looking Statements
This news release includes certain “forward-looking
statements” under applicable Canadian securities legislation.
These statements relate to future events or the Company’s future
performance, business prospects or opportunities. Forward-looking
statements include, but are not limited to, the impact of a
rebranding of the Company, the future development and exploration
potential of the Marimaca Project. Actual future results may differ
materially. 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
Company’s documents filed from time to time with the securities
regulators in the Provinces of British Columbia, Alberta,
Saskatchewan, Manitoba, Ontario, New Brunswick, Nova Scotia, Prince
Edward Island and Newfoundland and Labrador. 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.
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