New Pacific Reports High Recovery of Silver Achieved FOR Sulphides and Transitional Mineralized Materials from Silver SAND, Bolivia
NEWS RELEASE
Trading Symbol: TSX-V: NUAG / OTCQX: NUPMF
NEW PACIFIC REPORTS HIGH RECOVERY OF SILVER ACHIEVED FOR SULPHIDES AND
TRANSITIONAL MINERALIZED MATERIALS FROM SILVER SAND, BOLIVIA
VANCOUVER, British Columbia – February 7, 2019 – New Pacific Metals Corp. (TSX -V:NUAG)
(OTCQX:NUPMF) (the “Company”) is pleased to announce the preliminary results of the first
metallurgical test work for its Silver Sand project in Potosi, Bolivia. Metallurgical sampling and test
work commenced in September 2018 – the flotation recovery and bottle roll leaching test works for
the transition and sulphide mineralized materials have been completed and test work on the oxides
is under way. All tests, including column leaching test works, are expected to be completed by the
end of April 2019. P ositive recovery results have been achieved in the extraction of s ilver by the
processes of flotation and direct cyanidation from the initial metallurgical test work.
HIGHLIGHTS OF THE PRELIMINARY RESULTS OF COMPLETED TEST WORKS
Sulphide materials have reported 96.0% silver recovery by rougher -scavenger flotation and
the high silver extraction of 96.7% when leached in a bottle-roll with cyanide solution.
Transition materials achieved 86.8% recovery of silver by flotation and the high extraction of
97.0% by cyanidation in bottle roll test.
Test results indicate that the sulphide and transition type mineralized materials are non-
refractory as per the high silver recoveries achieved during the direct cyanidation at
atmospheric pressure.
The mineralized materials were measured to be mostly in the soft to-medium competent
level and abrasion from low-to medium values. Consequently, a lower capital expenditure
and operating cost would be required for the comminution circuit.
PROGRAMS OF METALLURGICAL TESTS
Half drilled core samples of oxides, transition and sulphides , representing naturally heterogeneous
distribution of oxidation degree, silver grades and lithology of the mineralized materials at the Silver
Sand minerals deposit , were collected to produce different composite samples . Four geo -
metallurgical test work programs ( Mineral Characterization, Comminution, Flotation and Leaching)
were developed on the se samples. Six metallurgical domains (MET1 to MET6) were identified for
the flotation and leaching test work and also six geological domains (GEO1 to GEO6) were branded
for the comminution test work. This study methodology has allowed creating ore-specific test works
that are producing high silver recovery results at this first stage of the metallurgical program.
Flotation
The test works of flotation were completed by SGS del Peru. Half drilled -core samples were
collected to produce three -master composite samples : oxides, transition and sulphides. The
flotation program was composed of rougher -scavenger tests at different size s, a mixture of
collectors, collector amount and pH. Collectors from the chemical family of Xanthates,
Hydroxamates and Dithiophosphates were tested. They were: PAX (potassium amyl xanthate), SIPX
(sodium isopropyl xanthate), DANA468, and OX100.
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Eighteen rougher-scavenger flotation tests for the transition (FLOATMET 5 composite) and sulphide
(FLOATMET 6 composite) types have been completed. Some of the results are presented in Table 1.
Figure 1 shows the flotation cells when transition and sulphide types we re processing. Table 1
presents silver and sulphide recoveries after floating for 20 minutes the sulphide and transition
materials at specific process conditions. The flotation for the oxide materials is under way.
Figure 1. Froth Formation for Silver Extraction from Transition and Sulphide Materials
The best silver recoveries to the rougher -scavenger concentrate were achieved using PAX as the
main collector for both sulphide and transition materials. The silver recovery of 96% was the best
result for sulphides materials and 86.8% was for the transition materials. Results so far suggest the
use OX100 as a secondary collector to improve silver extraction from transition materials. Similar
recoveries we re obtained at natural pH and the higher pH of 9. Though the flotation results are
promising, they can be optimized at the second stage of the metallurgical test work program.
Table 1. Partial Results for Rougher-Scavenger Test Work
Type of
Materials
Head Assay Flotation conditions Recovered to
Concentrate
Ag,
g/t
Ssulphide,
%
P80,
µm Collector pH Ag,
%
Ssulphide,
%
Sulphide
(FLOATMET 6) 123 1.63
74 PAX, 45g/t 9 96.0 98.4
74 PAX, 45g/t natural 95.5 97.2
74 PAX, 30g/t
SIPX, 15g/t natural 94.9 97.3
74 PAX, 30g/t
OX100, 15g/t natural 94.8 97.3
Transition
(FLOATMET 5) 123 1.01
74 PAX, 30g/t
OX100, 15g/t natural 86.8 94.8
74 PAX, 45g/t natural 85.1 92.4
74 PAX, 45g/t 9 85.2 94.8
74 PAX, 30g/t
DANA468, 15g/t natural 85.2 93.4
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It is worth mentioning that similar silver recoveries were obtained for the sulphide materials at the
particle size of P80 105µm and 74µm; being 92.8% at the biggest material size and 93.8% at 74µm
for the flotation of 12 minutes long. These results suggest that the silver minerals seem to be
already liberated at the size of 105µm which would give the opportunity to use a smaller
comminution circuit.
Bottle Roll Leaching
Four master composite samples were prepared from half drilled cores for the execution of leaching
tests with sodium cyanide solution (NaCN) of which o ne composite sample comprise s cores of
sulphide materials (LEACHMET 6), the other is made of transition materials (LEACHMET 5) and two
composites were composed of oxide materials (LEACHMET 1 and LEACHMET 4).
Direct cyanidation leaching in bottle -roll under conventional and intense conditions has been
completed for the sulphide and transition materials. Nineteen tests were carried out considering
different materials sizes, cyanide solution strength, air or oxygen sparging and different
temperatures. Each bottle roll test was conducted at atmospheric pressure during 72 hours. Some
of these leach test results are presented in Table 2.
Bottle roll leaching of oxides is underway at SGS del Peru.
Table 2. Partial Results for Cyanidation Bottle-Roll Leaching
Type of
Materials
Head Assay Leaching conditions
Ag
Recovery,
%
Ag,
g/t
Ssulphide,
%
Cu,
%
P80,
µm
Cyanide
Solution
Strength,
%w/v of NaCN
Temperature,
oC
Air or
Oxygen
Sparged
Sulphide
(LEACHMET 6) 124 2.12 0.03
50 0.3 57.4 Oxygen 96.7
74 0.4 29.4 Oxygen 94.0
50 0.3 26.1 Oxygen 93.6
74 0.3 29.4 Oxygen 92.8
Transition
(LEACHMET 5) 157 1.45 0.04
50 0.3 56.0 Oxygen 97.0
50 0.3 25.6 Oxygen 94.0
74 0.3 28.1 Oxygen 93.5
74 0.4 29.8 Oxygen 93.3
High silver extractions of up to 97% were achieve d for sulphide and transition materials by intense
cyanidation in bottle-rolls using oxygen at 56 – 57oC, as shown in Table 2. None of the samples were
pre-treated before the cyanidation; which is an indication of the liberation of the silver grains at the
tested materails size and/or low -amount encapsulation in pyrite. Therefore, it can be claimed that
the mineralized materials at Silver Sand are non-refractory. The texture and liberation will be
confirmed with the QEMSCAN assays that are under way. These leaching results are very
encouraging and they could be further improved in the next stage of the metallurgical program.
Column Leaching
The test works of column leaching are in progress at SGS del Peru and are expected to be completed
by the end of April 2019.
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Comminution
The test works of comminution were completed by SGS del Peru . Four geological domains were
tested for Crushing Work Index (CWi), Ball Work Index (BWi) and Abrassion Index (Ai). These
domains represent the different rock lithology, type and intensity of alteration and material type
that exist at the current drilled area of the Silver Sand deposit.
Twenty-one samples were tested . CWi reported the energy consumption between 4.8 and
11.3kWh/t and the BWi measurements were from 4.8 to 15.9kWh/t, with only one sample above 14
KW/t. Thus, the majority of the samples fell in the category of soft and medium competency level
for crushing and grinding. Consequently, a relatively low capital expenditure and operating cost
could be expected for the comminution circuit. The Ai reported values between 0.0595 and 0.5363.
Oxides and transition materials produced values below 0.3 , which corresponds to low abras ion.
Sulphide materials reported the highest values in the range of medium abrasion behaviour.
Mineral Characterization
The test works of mineral characterization are being executed by the Research Centre for Mining
and Metallurgy (CIMM) and Oruro Technical University (UTO) , Bolivia. The mineral characterization
and Sink & Float tests are to assess the mineral response to gravity separation. The tests are
expected to be complete by the end of February 2019.
The Company is very pleased with the positive results achieved so far from the completed test works.
The results suggest that the mineralized materials from Silver Sand project could be amenable for
extraction of silver by conventional flotation or direct-intense cyanidation at atmospheric pressure
at large scale. This is just the first stage of the metallurgical test work program and silver extraction
rates can still be improved by further tuning the parameters of test works.
Technical information contained in this news release and the test programs have been designed and
prepared by Mr. Alberto Galvez, an independent consulting metallurgist and a registered member of
the Australasian Institute of Mining and Metallurgy (AusIMM ) and reviewed and approved by Alex
Zhang, P.Geo., Vice President of Exploration of the Company , who is a Quali fied Person for the
purposes of National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).
ABOUT NEW PACIFIC
New Pacific is a Canadian exploration and development company which owns the Silver Sand Project
in Potosí Department of Bolivia, the Tagish Lake gold project in Yukon, Canada and the RZY Project in
Qinghai Province, China. Its largest shareholders are Silvercorp Metals Inc . and Pan American Silver
Corp., one of the world's largest primary silver producers, which operates six mines, including the
San Vicente mine located in the Potosí Department of Bolivia.
For further information, contact:
New Pacific Metals Corp.
Gordon Neal
President
Phone: (604) 633-1368
Fax: (604) 669-9387
www.newpacificmetals.com
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