Heap Leach Silver Recoveries of 80%
– Flowsheet Demonstrates Superior
Performance
VANCOUVER, BC, Oct. 19, 2021 /CNW/ - New Pacific Metals
Corp. ("New Pacific" or the "Company") (TSX: NUAG) (NYSE
American: NEWP) is pleased to announce the results from the
2020-2021 metallurgical test program at its flagship Silver Sand
deposit, Bolivia.
HIGHLIGHTS:
- 80% silver recovery achieved through the heap leach process
method.
- Heap leach process flowsheet demonstrates significantly
superior performance due to anticipated lower capital intensity and
operational costs versus other alternatives to produce silver doré
on site.
- Heap leach performance of oxide and transitional mineralization
is similar.
- Oxide and transitional material combined comprise approximately
80% of the resource, which includes Measured and Indicated Mineral
Resources of 35.39 Mt at a grade of 137 grams per tonne ("g/t")
silver containing 155.85 Moz of silver and Inferred Mineral
Resource of 9.84 Mt g/t silver, containing 35.55 Moz of silver
(refer to the Company's news release dated April 14, 2020).
- Adoption of a heap leach process flowsheet may allow for a
lower cut-off grade in the updated Mineral Resource Estimate, which
will be determined through continued test work.
Dr. Mark Cruise, CEO of New
Pacific, notes: "The positive results from this metallurgical
program, combined with the results from the 2019 Metallurgical
Study, significantly de-risk the Silver Sand Project. We anticipate
the project will move forward as a low-cost, open-pit heap leach
operation. The Preliminary Economic Assessment ("PEA") for the
Silver Sand Project, including an updated Mineral Resource
Estimate, is expected to be published in first half of 2022 and
will incorporate results from our current 38,000-metre resource
expansion drill program."
METALLURGICAL TEST WORK RESULTS
Metallurgical testing was completed using three representative
master composite samples with grades ranging from 90 g/t to 120 g/t
silver of oxide, transitional (oxide-sulphide) and sulphide (fresh)
mineralization, together with six grade variability composites.
The tested material was created from over 300 core samples
sourced from four metallurgical drill holes completed in the first
quarter of 2020. Please refer to the Company's news release dated
July 13, 2020 for further
details.
A summary of the heap leach column test results and outcomes of
additional work are presented below.
Heap Leach Column Test Work
- A 140-day heap leach column test was completed on approximately
100 kg of transitional master composite material using a one-half
inch crush size, a sodium cyanide (NaCN or "reagent") concentration
of 0.6 grams per litre ("g/l") and an irrigation rate of 10 liters
per hour per metre squared ("l/hr/m2").
- At 120 days, testing achieved an 80% final recovery with a
consumption of 1.2 kg/t of reagent.
- The results complement the work completed in the 2019
Metallurgical Study for heap leach of oxide material, which
demonstrated recoveries of 84% and 87% for low grade and median
grade oxide material, respectively. Please refer to the Company's
news release dated August 20, 2019
for further details.
- Results indicate the heap leach performance of oxide and
transitional material is similar, such that the two types of
material may potentially be processed as a single metallurgical
entity. Consequently, the oxide and transitional material will be
referred to as "Transitional material".
Coarse Bottle Roll Testing
- Bottle roll testing was completed for a range of fine grinds
(53 micron to 100 micron ("µm")) as well as a coarse grind of -2
millimetres ("mm").
- Tests were performed on the time of leaching, reagent
concentration, effects of dissolved oxygen, and the impact of lead
nitrate.
- The best conditions for fine grind were determined at 72 hours
and resulted in silver recovery for oxide, transitional and
sulphide material of 91%, 94% and 81%, respectively.
- The coarse grind results demonstrated good correlation to the
heap leach performance.
- Bottle roll testing was also conducted on concentrates produced
from flotation.
Flotation Test Work
- Tested grind size (on rougher recoveries) of 100 µm, 75 µm and
53 µm. A grind size of 75 µm was selected as the most
favourable.
- Trialed flotation time, completed cleaner performance tests and
locked cycle tests.
- Locked cycle tests achieved silver recoveries of 67%, 83% and
87% for oxide, transitional and fresh composite samples,
respectively, to produce silver concentrate grades ranging from
12,000 g/t silver in oxide concentrate to 2,200 g/t silver in a
pyrite-silver sulphide concentrate with low base metal
content.
COMPARATIVE PROCESS FLOWSHEET MODELLING
The Company conducted a comparative process flowsheet modelling
study to determine relative performance between several technically
viable processing path solutions, as follows.
Processing options for silver doré production:
- Heap leach of all material – oxide, transitional and
sulphide;
- Heap leach of Transitional Material only;
- Heap leach of low-grade material and grinding plus leaching /
Merryl Crowe of higher-grade
mineralization;
- Grinding plus leaching / Merryl
Crowe;
- Grinding plus single stage flotation and additionally leaching
the flotation tail; and
- Grinding and single stage flotation with leaching of the
concentrate.
Processing options for pyrite-silver concentrate production:
- Heap leach of oxide and Transitional Material, and grinding
followed by single stage flotation of the sulphide component;
- Grinding plus single stage flotation; and
- Grinding plus single stage flotation and additionally leaching
the flotation tail.
Results of the comparative study indicate a heap leach operation
is significantly superior to all other modeled options. This is due
to several factors, including:
- Anticipated lower capital and operating costs required for a
heap leach operation compared to the other potential mineral
processing solutions;
- Relatively small difference in recovery for the oxide and
transitional material, which forms the majority of the current
Mineral Resources; and
- Potential for lower cut-off grades leading to a possible
increase in mineralization available for processing.
The comparative process flowsheet modeling study was completed
for the purpose of selecting a process flowsheet for the project
PEA and is not intended to provide guidance on the project
economics. No mine plan or economic model of the project has
been produced. The comparative process studies were completed
for the purpose of determining an optimal processing path, which
determines future metallurgical testing efforts and provides a
basis for the PEA analysis. Guidance on the project economics and
profitability, assuming a heap leach process flowsheet, will be
provided in the PEA.
Further work will focus on the optimization of a heap leach
process flowsheet. This decision is supported by the large
difference between the results of heap leach process modeling and
the results of the next most likely processing method.
New Pacific acknowledges that a significant growth in the
sulphide component of the Mineral Resource could change the
comparative modelling results and subsequent potential implications
of future test work. This could potentially lead to a Phase
II processing solution in the contemplated life-of-mine operation
plan.
ADDITIONAL TEST WORK
Mineralogy studies and heavy
media separation test work was completed at SGS Lakefield in
Ontario, Canada. Mineral particle
sorting test work was completed at TOMRA Sorting
Solutions' facility in Wedel/Hamburg, Germany.
Mineral particle sorting and heavy media separation results
demonstrated poor performance in the oxide and transitional
material, but may have future applications with sulphide
processing, should the size of the sulphide component of the
Mineral Resources increase significantly.
SGS del Perú S.A.C. in Lima,
Peru ("SGS Lima") completed grind hardness and abrasion test
work, which indicated the Bond Ball Mill Index for oxide,
transitional and sulphide materials would be 16.6 kilowatt-hour per
dry metric tonne ("kWhr/dmt"), 14.1 kWhr/dmt, and 12.3 kWhr/dmt,
respectively, and considered generally "moderate to hard" for
purposes of grinding.
The abrasion index for oxide, transitional and sulphide
materials is 0.31 grams ("g"), 0.33 g, and 0.37 g, respectively,
which indicates that the rock is slightly abrasive. Major
wear-related issues are not expected to arise from processing the
material.
FUTURE METALLURGICAL WORK
An additional 115 kg of
drill core coarse reject material has been delivered to SGS Lima
for -2mm coarse bottle roll variability test work. The results will
be used to refine the relationship between the oxidation state of
the mineralization and the silver recovery in the transitional and
sulphide components of the Mineral Resources. This data will also
help refine the selection of composites for future anticipated
prefeasibility-level column leach tests.
Additional work to support more advanced studies includes:
- Determination of the effect of crush size and irrigation rates
on silver recoveries for column leach testing;
- Rock permeability testing; and
- Additional environmental characterization.
QUALIFIED PERSON
The scientific and technical
information contained in this news release has been reviewed and
approved by Gary DeSchutter, M.Sc.,
P. Geo., Manager Silver Sand Project, who is a Qualified Person for
the purposes of National Instrument 43-101 Standards of Disclosure
for Mineral Resources ("NI 43-101").
The metallurgical work described in this news release was
conducted at SGS Lima, SGS Lakefield,
Ontario, Canada and TOMRA Sorting Solutions' facility in
Wedel/Hamburg, Germany. The work
was completed under the supervision of Andy
Holloway, P.Eng., Principal Process Engineer of AGP Mining
Consultants Inc. and Jillian Gong, a
consultant of the Company. The final CSA Global metallurgical
report was peer-reviewed by Andrew
Sharp, P.Eng., FAusIMM., Principal Mining Engineering at CSA
Global.
ABOUT CSA GLOBAL
CSA Global is a geological, mining
and management consulting company providing strategic mining
services and advice to companies in the international mining
industry. Together with its parent company ERM, CSA Global has
access to more than 5,500 people specializing in environmental,
health, safety, risk, social and sustainability related services in
over 40 countries and territories working out of over 160 offices
around the world.
ABOUT SGS
SGS is one of the world's leading
inspection, verification, testing and certification companies. SGS
is recognized as the global benchmark for quality and integrity.
With more than 89,000 employees, SGS operates a network of over
2,600 offices and laboratories around the world. Bankable
flowsheets help prove the viability of a gold mining project to
financers and stakeholders. SGS has, in this regard, earned a
global reputation as a proven leader in the development of
transparent, bankable flowsheets for a wide range of mineral and
metal extraction operations.
ABOUT NEW PACIFIC
New Pacific is a Canadian
exploration and development company of precious metal projects,
including the flagship Silver Sand Project, the Silverstrike
Project and the Carangas Project, all of which are located in
Bolivia. The Company is focused on
progressing the development of the Silver Sand Project, while
growing its Mineral Resources through the exploration and
acquisition of properties in the Americas.
For further information, please
contact:
Stacey Pavlova, CFA
VP, Investor Relations and Corporate Communications
New Pacific Metals Corp.
Phone: (604) 633-1368
U.S. & Canada toll-free:
1-877-631-0593
E-mail: info@newpacificmetals.com
www.newpacificmetals.com
To receive company news by e-mail, please register using New
Pacific's website at www.newpacificmetals.com.
CAUTIONARY NOTE REGARDING FORWARD-LOOKING INFORMATION
Certain of the statements and information in this news
release constitute "forward-looking statements" within the meaning
of the United States Private Securities Litigation Reform Act of
1995 and "forward-looking information" within the meaning of
applicable Canadian provincial securities laws. Any
statements or information that express or involve discussions with
respect to predictions, expectations, beliefs, plans, projections,
objectives, assumptions or future events or performance (often, but
not always, using words or phrases such as "expects", "is
expected", "anticipates", "believes", "plans", "projects",
"estimates", "assumes", "intends", "strategies", "targets",
"goals", "forecasts", "objectives", "budgets", "schedules",
"potential" or variations thereof or stating that certain actions,
events or results "may", "could", "would", "might" or "will" be
taken, occur or be achieved, or the negative of any of these terms
and similar expressions) are not statements of historical fact and
may be forward-looking statements or information. Such statements
include, but are not limited to: statements regarding anticipated
exploration, drilling, development, construction, and other
activities or achievements of the Company; timing of receipt of
permits and regulatory approvals; and estimates of the Company's
revenues and capital expenditures.
Forward-looking statements or information are subject to a
variety of known and unknown risks, uncertainties and other factors
that could cause actual events or results to differ from those
reflected in the forward-looking statements or information,
including, without limitation, risks relating to: global economic
and social impact of COVID-19; fluctuating equity prices, bond
prices, commodity prices; calculation of resources, reserves and
mineralization, general economic conditions, foreign exchange
risks, interest rate risk, foreign investment risk; loss of key
personnel; conflicts of interest; dependence on management,
uncertainties relating to the availability and costs of financing
needed in the future, environmental risks, operations and political
conditions, the regulatory environment in Bolivia and Canada, risks associated with community
relations and corporate social responsibility, and other factors
described under the heading "Risk Factors" in the Company's Annual
Information Form for the year ended June 30,
2021 and its other public filings. This list is not
exhaustive of the factors that may affect any of the Company's
forward-looking statements or information.
The forward-looking statements are necessarily based on a
number of estimates, assumptions, beliefs, expectations and
opinions of management as of the date of this news release that,
while considered reasonable by management, are inherently subject
to significant business, economic and competitive uncertainties and
contingencies. These estimates, assumptions, beliefs,
expectations and options include, but are not limited to, those
related to the Company's ability to carry on current and future
operations, including: the duration and effects of COVID-19 on our
operations and workforce; development and exploration activities;
the timing, extent, duration and economic viability of such
operations; the accuracy and reliability of estimates, projections,
forecasts, studies and assessments; the Company's ability to meet
or achieve estimates, projections and forecasts; the stabilization
of the political climate in Bolivia; the Company's ability to obtain and
maintain social license at its mineral properties; the availability
and cost of inputs; the price and market for outputs; foreign
exchange rates; taxation levels; the timely receipt of necessary
approvals or permits, including the ratification and approval of
the Mining Production Contract with COMIBOL by the Plurinational
Legislative Assembly of Bolivia;
the approval of the mining association agreement for the
Silverstrike Project by AJAM; the ability of the Company to convert
the exploration licenses at the Carangas Project to AMC; the
ability to meet current and future obligations; the ability to
obtain timely financing on reasonable terms when required; the
current and future social, economic and political conditions; and
other assumptions and factors generally associated with the mining
industry.
Although the forward-looking statements contained in this
news release are based upon what management believes are reasonable
assumptions, there can be no assurance that actual results will be
consistent with these forward-looking statements. All
forward-looking statements in this news release are qualified by
these cautionary statements. Accordingly, readers should not
place undue reliance on such statements. Other than specifically
required by applicable laws, the Company is under no obligation and
expressly disclaims any such obligation to update or alter the
forward-looking statements whether as a result of new information,
future events or otherwise except as may be required by law.
These forward-looking statements are made as of the date of this
news release.
CAUTIONARY NOTE TO US INVESTORS
The disclosure in this news release and referred to herein
was prepared in accordance with NI 43-101 which differs
significantly from the requirements of the U.S. Securities and
Exchange Commission (the "SEC"). The terms "proven mineral
reserve", "probable mineral reserve" and "mineral reserves" used in
this news release are in reference to the mining terms defined in
the Canadian Institute of Mining, Metallurgy and Petroleum
Standards (the "CIM Definition Standards"), which definitions have
been adopted by NI 43-101. Accordingly, information contained
in this news release providing descriptions of our mineral deposits
in accordance with NI 43-101 may not be comparable to similar
information made public by other U.S. companies subject to
the United States federal
securities laws and the rules and regulations thereunder.
Investors are cautioned not to assume that any part or all of
mineral resources will ever be converted into reserves. Pursuant to
CIM Definition Standards, "Inferred mineral resources" are that
part of a mineral resource for which quantity and grade or quality
are estimated on the basis of limited geological evidence and
sampling. Such geological evidence is sufficient to imply but
not verify geological and grade or quality continuity. An
inferred mineral resource has a lower level of confidence than that
applying to an indicated mineral resource and must not be converted
to a mineral reserve. However, it is reasonably expected that the
majority of inferred mineral resources could be upgraded to
indicated mineral resources with continued exploration. Under
Canadian rules, estimates of inferred mineral resources may not
form the basis of feasibility or pre-feasibility studies, except in
rare cases. Investors are cautioned not to assume that all or
any part of an inferred mineral resource is economically or legally
mineable. Disclosure of "contained ounces" in a resource is
permitted disclosure under Canadian regulations; however, the SEC
normally only permits issuers to report mineralization that does
not constitute "reserves" by SEC standards as in place tonnage and
grade without reference to unit measures.
Canadian standards, including the CIM Definition Standards
and NI 43-101, differ significantly from standards in the SEC
Industry Guide 7.Effective February 25,
2019, the SEC adopted new mining disclosure rules under
subpart 1300 of Regulation S-K of the United States Securities Act
of 1933, as amended (the "SEC Modernization Rules"), with
compliance required for the first fiscal year beginning on or after
January 1, 2021.The SEC Modernization
Rules replace the historical property disclosure requirements
included in SEC Industry Guide 7.As a result of the adoption of the
SEC Modernization Rules, the SEC now recognizes estimates of
"Measured Mineral Resources", "Indicated Mineral Resources" and
"Inferred Mineral Resources". In addition, the SEC has amended its
definitions of "Proven Mineral Reserves" and "Probable Mineral
Reserves" to be substantially similar to corresponding definitions
under the CIM Definition Standards. During the period leading up to
the compliance date of the SEC Modernization Rules, information
regarding mineral resources or reserves contained or referenced in
this news release may not be comparable to similar information made
public by companies that report according to U.S. standards. While
the SEC Modernization Rules are purported to be "substantially
similar" to the CIM Definition Standards, readers are cautioned
that there are differences between the SEC Modernization Rules and
the CIM Definitions Standards. Accordingly, there is no assurance
any mineral reserves or mineral resources that the Company may
report as "proven mineral reserves", "probable mineral reserves",
"measured mineral resources", "indicated mineral resources" and
"inferred mineral resources" under NI 43-101 would be the same had
the Company prepared the reserve or resource estimates under the
standards adopted under the SEC Modernization
Rules.
View original content to download
multimedia:https://www.prnewswire.com/news-releases/new-pacific-announces-results-of-the-metallurgical-test-program-at-its-silver-sand-project-301402872.html
SOURCE New Pacific Metals Corp.