Nevada Zinc Reports Excellent Results From Initial Metallurgical Test Work
06 April 2016 - 10:01PM
Nevada Zinc Corporation (“Nevada Zinc” or the “Company”)
(TSX-V:NZN) is pleased to announce positive initial results from
mineralogical and sample processing studies completed on
representative non-sulphide mineralized material from its Lone
Mountain Zinc project near Eureka Nevada.
Importantly,
initial test work showed that by using a 3.03 specific gravity
(“SG”) ‘cut point’ in Heavy Liquid Separation (“HLS”) analysis, 79%
of the zinc reported to a high grade zinc concentrate that would be
a potentially saleable concentrate grading 36.7% zinc. At a SG of
2.85, 92% of the zinc reported to the concentrate. The
mineralization and non-mineralized ‘gangue’ were found to have
rather simple mineralogy and the HLS studies indicate that 90% of
the potentially acid consuming carbonate gangue can be rejected
using only HLS. The rejection of the potentially acid
consuming carbonate minerals using only HLS is important given a
reduction in non-zinc carbonate content would significantly reduce
overall acid consumption if acid leaching were to be used in any
eventual mill flow sheet. The Company continues to explore
alternatives that have potential to drive value creation through
standard and as well as innovative mineral processing solutions.
President and CEO, Bruce Durham commented on the
sample processing results; “Knowing that the high grade near
surface mineralization we discovered on our Lone Mountain project
was not typical sulfide mineralization, we were keenly aware of the
need to evaluate the mineralogy of the mineralization and also
determine processing options earlier in the exploration phase than
typically required. We decided to initially investigate the
possibility of upgrading the mineralization with just Dense Media
Separation techniques using Heavy Liquid Separation testing as a
proxy. We were pleasantly surprised to find that firstly, the
mineralogy is rather simple and secondly that a simple process of
crushing, grinding and Dense Media Separation can be expected to
produce a concentrate of sufficient grade and quality to be a
shippable and saleable product without any further beneficiation.
Dense Media Separation plants are becoming much more common and
less costly and in our case may prove to be a simple way to very
significantly reduce both capital and operating costs in any
eventual process plant at Lone Mountain.”
Highlights
- Zinc recovery values of up to 92% at a 2.85 SG or 79% at a 3.03
SG, the latter of which produced a zinc concentrate grade of
36.7%
- Zinc in the samples studied is nearly all in the form of
hemimorphite and smithsonite (zinc oxide and zinc carbonate) while
lead occurs as cerrusite (lead carbonate)
- Non-zinc and lead bearing material (gangue) is dominated by
simple mineralogy: essentially dolomite and calcite
- Virtually no sulphide mineralization is present
- Simple mineralogy is a key for simplicity in any future mill
flow sheet design
- The zinc and lead minerals have significantly higher SG than
the gangue minerals making DMS an ideal way to produce a high grade
concentrate for either shipping directly for off-site processing or
for further on-site upgrading using leaching technology or other
techniques
- Very favourable results in HLS testing that produced a high
grade concentrate with low iron and deleterious elements
- Rejection of 90% of Ca-Mg (dolomite calcite) potentially acid
consuming
- All fractions tested produced similar results (No testing
completed on the <0.85mm fraction)
- Next phase, leach testing (dissolution testing) is currently
underway
Mineralogy and HLS Testing
Mineralized samples were submitted to Process Mineralogical
Consulting of Maple Ridge B.C.. Various tests
were performed including optical mineralogy, ICP-OES analysis, and
powder X-ray diffraction to determine mineralogical compositions.
Polished blocks were created for presentation to the Tescan
Integrated Mineral Analyser (“TIMA”) in order to determine the
mineral content as well as to determine the liberation and
association constraints of the zinc bearing minerals which may
affect the processing of the material for producing a zinc
concentrate.
HLS testing was carried out in conjunction with the
mineralogical studies with a view to determining the grade-recovery
relationship for a composite sample of mineralization from the Lone
Mountain Property in Nevada. The sample was shipped to Met-Solve in
Langlely B.C.. Following an established protocol for evaluating the
response of mineralized material to HLS and based on the
mineralogical investigations, Met-Solve personnel reduced the size
of the mineralized material and the sample was then split in half
using a large riffle splitter. Zinc deportment by particle size was
determined prior to the HLS testing. Subsequent to particle size
analysis, 16kg of sample was washed and screened and three prepared
size fractions were tested at four specific gravity cut points. The
resulting products were assayed by sodium peroxide fusion at
Met-Solve Analytical and a duplicate assay was done on at least one
sample from each size fraction for quality control. Only assaying
was carried out on the fines material (<.85mm screened
material). A robust QA/QC protocol was not established or completed
on the various sample fractions. Met-Solve and Nevada Zinc have
determined that the process as outlined and completed is sufficient
for the stage of the work being completed. A process of back
calculating the grade of the sample was also carried out to ensure
the reliability of the results generally.
The primary conclusions of the HLS testing are summarized by
Met-Solve as: “In general the sample responded favourably to heavy
liquid separations; conventional trade-offs between concentrate
grade and zinc recovery can be observed in the results. At an SG
cut point of 2.85, 92% of the zinc was recovered into 53% of the
mass at a grade of 25.1% Zn."
“At an SG of 3.03, 79% of the zinc was recovered into 31% of the
mass at a grade of 36.7% This indicates that a potentially saleable
concentrate can be produced by a DMS (dense media separation) only
process. Regarding the ability of HLS to lower the overall Mg-Ca
carbonate content of the resultant concentrate Met-Solve conclude;
At a SG cut point of 3.03, 90% of the calcium and magnesium was
rejected while 79% of the zinc was recovered into 31% of the mass
at a grade of 36.7%. In the RECOMMENDATIONS portion of the
Met-Solve report, they report as follows; “The heavy liquid
separation test results are encouraging. The results show that
production of a high grade zinc product and rejection of the
majority of the calcium and magnesium is attainable. From
experience, Met-Solve have found agreement between HLS and DMS
results to be very good.” Met-Solve recommends that further testing
using a pilot scale Condor DMS plant be considered.
About The Lone Mountain Project
The Lone Mountain Project (the “Property”),
comprised of 218 claims covering approximately 4,000 acres and 100%
owned by the Company through its wholly-owned US subsidiary, is
subject to certain terms as per the underlying lease agreements
disclosed on SEDAR (press release June 24, 2014 and various other
filings including the Company’s MD&As filed on SEDAR).
The Property is located in east-central Nevada
and is easily accessible via paved and gravel roads northwesterly
from Eureka where all essential services are available. The
Property includes the Mountain View Mine that is reported to have
produced some 5 million pounds of zinc and some 0.6 million pounds
of lead from small scale very high grade non-sulphide
mineralization Mineralization is located within brecciated Devils
Gate Limestone and is thought to be structurally controlled,
perhaps at the intersection of two fault systems.
Bruce Durham, P.Geo, is a qualified person as
that term is defined by National Instrument 43-101 on behalf of the
Company and has approved the scientific and technical content
contained in this press release.
Ish Grewal, P.Eng is a is a qualified person as
that term is defined by National Instrument 43-101 on behalf of
Met-Solve Laboratories Inc. and has approved the scientific and
technical content contained in this press release ascribed to
Met-Solve Laboratories Inc.
The Company has granted stock options to
purchase 750,000 shares to directors, officers and consultants
under the Company’s stock option plan at a price of $0.39 per share
with an expiry date of April 6, 2021.
About Met-Solve
Laboratories
Met-Solve Laboratories Inc., located in the
Metro Vancouver area, is a B.C. based extractive metallurgy
laboratory. Extractive metallurgy, the science of separating target
minerals and metals from mineralized rock, is one of the key
components in the determination of the feasibility of any mining
project. Met-Solve is well versed in determining how responsive a
particular ore body is to a variety of mineral beneficiation
techniques, information which can then be used to determine
recoveries, grades, processing costs and environmental impacts.
Since inception in 2007, Met-Solve and its team of professional
engineers have worked with mining projects of all sizes and at all
stages of production from early stage geological assessments to
metallurgical audits of operating plants. The depth and diversity
of experience within the Met-Solve team has allowed the laboratory
to develop customized flowsheets for the unique needs of all
clients and continue to help clients achieve their goals for their
mining projects.
About Nevada Zinc
Nevada Zinc is a discovery and development
driven, mineral exploration company with a proven management team
focussed on identifying unique opportunities in mineral exploration
that can provide significant value opportunity to its shareholders.
The Company’s existing projects are located in Nevada and the
Yukon.
Neither the TSX Venture Exchange nor its Regulation Services
Provider (as that term is defined in the policies of the TSX
Venture Exchange) accepts responsibility for the adequacy or
accuracy of this release.
This news release may contain forward-looking statements
including but not limited to comments regarding the timing and
content of upcoming work programs, geological interpretations,
receipt of property titles, potential mineral recovery processes,
etc. Forward-looking statements address future events and
conditions and therefore, involve inherent risks and uncertainties.
Actual results may differ materially from those currently
anticipated in such statements.
For further information contact:
Nevada Zinc Corporation
Suite 1660 141 Adelaide St. West
Toronto, Ontario M5H 3L5
Tel: 416-504-8821
Bruce Durham, President and CEO
bdurham@nevadazinc.com
www.nevadazinc.com
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