Silver Bull Resources, Inc. (TSX:SVB)(NYSE MKT:SVBL) ("Silver
Bull") is pleased to provide preliminary results for its
metallurgical test program completed on the silver and zinc
mineralization at the Sierra Mojada project located in the state of
Coahuila, Northern Mexico. The results of this news release pertain
to a series of bottle roll tests on the silver mineralization from
the "Centenario Zone" and pyro-metallurgical tests using a rotary
kiln from the "Red Zinc Zone."
Highlights include;
-- Silver recoveries from the Centenario Zone of up to 89% with an average
recovery of 83% silver across a variety of silver grade ranges.
-- The highest silver recoveries were achieved at a 75 micron grind using a
cyanide strength of 5 grams per liter over a 24 hour time period.
-- Roasting of the red zinc ore achieved up to 98.9% removal of zinc from
the ore via fuming - producing an almost pure zinc oxide concentrate
(approximately 80% zinc concentrate) at a 1,300 degrees Celsius roasting
temperature.
Summary of Silver Metallurgical Test Work
Testing on the silver ore at Sierra Mojada has been conducted by
Kappes, Cassiday and Associates ("KCA"), Reno. Work has focused on
cyanide leach recovery of the silver using "Bottle Roll" tests to
simulate an agitation leach system common on many mine sites.
Samples have been taken separately from drill core, mineralized
outcrop, and trenches from the "Centenario", "Fonteriza" and
"Shallow Silver" Zones of the deposit and have been crushed and
mixed to create either a "composite" sample representative of each
of the 3 zones, or a series of composite samples based on the
silver grade for each of the three zones.
The Centenario Zone is composed of a large silver oxide body
hosted along the "Centenario" fault and represents approximately
1/3rd of the silver mineralization seen at Sierra Mojada. It is
hosted along a buried east-west trending structure which lies
parallel and 300m to the north of the "Sierra Mojada" fault - which
hosts the Shallow Silver and Fonteriza Zones. The widest part of
the mineralization in the Centenario Zone occurs at the
intersection of the Centenario fault and a major north-south
trending fault which cross cuts the entire deposit. Like the
Shallow Silver Zone, a thick dolomite unit appears to be the
favorable host rock for the mineralization, especially when
immediately adjacent to fault zones. Drilling shows a high grade
core of silver mineralization grading in excess of 400 g/t Ag and
averaging greater than 100 g/t Ag sitting within a lower grade
large halo of silver mineralization less than 100 g/t Ag.
A summary of the initial diagnostic leach tests results on six
grade composites from the Centenario Zone is shown below.
----------------------------------------------------------------------------
NaCN
Grind concen- Ag Extracted Leach Consumption Addition
Sample size tration Grade Extracted Ag, Time, NaCN, Ca(OH)2,
ID (mm) (gpL) (g/t) Ag (g/t) (%) (hrs) kg/MT kg/MT
----------------------------------------------------------------------------
65442 0.075 5.00 172.36 153.44 89% 24 2.45 2.00
----------------------------------------------------------------------------
65438 0.075 5.00 105.81 93.57 88% 24 2.45 2.00
----------------------------------------------------------------------------
65444 0.075 5.00 103.99 82.11 79% 24 1.89 2.00
----------------------------------------------------------------------------
65443 0.075 5.00 41.55 34.01 82% 24 9.79 2.00
----------------------------------------------------------------------------
65437 0.075 5.00 43.34 35.44 82% 24 2.45 2.00
----------------------------------------------------------------------------
65441 0.075 5.00 40.07 32.19 80% 24 3.15 2.00
----------------------------------------------------------------------------
Preliminary observations from these results include;
-- Silver recoveries generally show an increase with higher grade.
-- 80% + recovery is seen in the lower grade silver ore.
-- Varying levels of cyanide consumption (NaCN) are attributed to variable
amounts of zinc and copper in the samples.
In addition to continuing tests assessing the silver recoveries
via cyanidation, studies are also planned to see if the "SART"
process (sulfidization, acidification, recycling and thickening)
can be applied at the backend of the leaching circuit. If
successful this may allow for the recycling of the cyanide in the
silver leaching circuit - potentially lowering cyanide costs, as
well as potentially recovering a portion of the zinc and copper we
also see in the ore. The SART process has been used successfully at
several full-scale mining operations including Newmont's Yanancocha
Mine in Peru, and more plants are currently under construction.
Summary of Zinc Metallurgical Test Work
Pyro-metallurgical test work on the zinc has been conducted at
Hazen Research, Inc. ("Hazen"), Colorado. Samples have been taken
from channel samples along the 1.5 kilometer strike length of the
"Red Zinc Zone" and have been crushed and mixed to form a composite
sample representative of the ore body. Initial tests have focused
on roasting the ore in a rotary kiln to fume off the zinc and
collect it as a zinc oxide concentrate. A summary of the results is
shown below.
----------------------------------------------------------------------------
Sample Size % Zn fumed from
Ore Conditions (grams) Zn Grade (%) original feed
----------------------------------------------------------------------------
RZ 1100 degrees C, 3:1 C:Zn 100 12.5 33.0
----------------------------------------------------------------------------
RZ 1200 degrees C, 3:1 C:Zn 100 12.5 86.9
----------------------------------------------------------------------------
RZ 1200 degrees C, 4:1 C:Zn 150 18.75 93.9
----------------------------------------------------------------------------
RZ 1300 degrees C, 3:1 C:Zn 100 12.5 98.9
----------------------------------------------------------------------------
Several preliminary observations can be made from these
results;
-- Zinc fuming shows an obvious increase in recovery with increasing
temperature.
-- A higher carbon to zinc ratio significantly increases zinc fuming at
lower temperatures.
The roasting of the zinc ore aims to simulate a "Waelz Kiln", a
kiln which is used extensively to recycle zinc from steel dust and
which regularly achieves recoveries in excess of 90%. In
considering this process, the zinc resource at Sierra Mojada has a
number of advantages; it lies in the state of Coahuila which is the
largest coal producing state in Mexico and would provide the fuel
to run the kiln, and it has a functioning railway right to site to
allow for easy transport of coal to the site and of the zinc
concentrate from the site without any significant build out costs.
Additional tests are underway to establish zinc oxide precipitation
parameters for the fumed zinc.
Tim Barry, President, CEO and director of Silver Bull states,
"We are extremely pleased with these preliminary metallurgical test
results for the silver and zinc mineralization. When we consider
silver oxide deposits often have recoveries in the low 60% range,
the results we see in the Centenario zone are exceptional. We are
also very pleased that we have been able to achieve the +90% fuming
of the zinc that we see with the Waelz kilning technique already
used in the industry. This, combined with the fact that we have a
functioning railway right to site is a serious positive for the
"mineability" of the zinc at Sierra Mojada. Our goal is to put out
a new resource update and have a viable flow sheet in place before
the end of the first quarter of 2013. We will then look to take
this project to the next level via a Preliminary Economic
Assessment."
Ongoing Metallurgical Activities
Silver: Tests are ongoing at KCA and results are expected from
bottle roll tests on the "Shallow Silver" and "Fonteriza" Zones
shortly. Once the preliminary program is complete, work will then
move to focus on optimizing recovery versus economics looking at
parameters such as head grade of the silver ore, grind size, and
cyanide concentration.
Zinc: Tests remain ongoing at Hazen to assess the
pyro-metallurgical recoveries on the zinc mineralization. With the
preliminary results now complete, a series using a larger sample
sizes will now be used to replicate the initial bench top
results.
In addition to the pyro-metallurgical tests at Hazen, Silver
Bull also has a full program underway at SGS Lakefield Research
Ltd. ("SGS") to assess hydro-metallurgical recovery potential on
the zinc through floatation, leaching, and dense media separation.
Previous historical tests showed +80% recovery of the zinc forming
concentrate grades of approx. 30% Zn on head grades containing +6%
Zn.
About the Shallow Silver Zone: The "Shallow Silver Zone" is an
oxide silver deposit (+/- zinc & lead), hosted along an
east-west trending fracture-karst system set in a cretaceous
limestone-dolomite sequence. At a 20g/t cutoff grade the Shallow
Silver Zone and has a measured resource of 3.023 million tonnes at
an average grade of 65.0 g/t for 6.343 million contained troy
ounces of silver, an indicated resource of 38.560 million tonnes at
an average grade of 50 g/t for 61.694 million contained troy ounces
of silver, and an inferred resource of 6.491 million tonnes at an
average grade of 45.0 g/t for 9.478 million contained troy ounces
of silver. The mineralized body averages between 30m - 90m thick,
up to 200m wide and remains open in all directions. Approximately
60% of the current 3.8 kilometer strike length is at or near
surface before dipping at around 6 degrees to the east.
Zinc Exploration Target: In addition to the silver resource,
Sierra Mojada also contains a significant "zinc oxide exploration
target" which sits directly below and adjacent to the Shallow
Silver Zone at its eastern end. The "Red" and "White" zinc zones
have been identified through historical data containing 3,733
channels and 1,045 Long holes over a 1.5 km strike length but has
too few diamond drill holes to presently delineate a NI43-101
compliant mineral resource. The zinc mineralization is composed of
hemimorphite and lesser smithsonite and forms a tabular body hosted
mostly within the upper dolomite along the east-west trending
Sierra Mojada fault. It is located 600 meters from a functioning
railway and has been periodically mined for zinc grading greater
than 20% over the last 100 years. An underground drill program
"twinning" a number of the historical long holes is currently
underway in the zinc zone to increase the confidence in the
historical data set.
About Silver Bull: Silver Bull is a US registered mineral
exploration company listed on both the NYSE MKT and TSX stock
exchanges and based out of Vancouver, Canada. The flagship "Sierra
Mojada" project is located 150 kilometers north of the city of
Torreon in Coahuila, Mexico and is highly prospective for silver
and zinc. Silver Bull also has two mineral exploration licenses in
Gabon, Central Africa, which are prospective for gold, manganese
and iron ore.
The technical information of this news release has been reviewed
and approved by Tim Barry, MAusIMM, a qualified person for the
purposes of National Instrument 43-101.
On behalf of the Board of Directors
Tim Barry, MAusIMM, Chief Executive Officer, President and
Director
Cautionary Note to U.S. Investors concerning estimates of
Measured, Indicated and Inferred Resources: This press release uses
the terms "measured resources", "indicated resources", and
"inferred resources" which are defined in, and required to be
disclosed by, NI 43-101. We advise U.S. investors that these terms
are not recognized by the United States Securities and Exchange
Commission (the "SEC"). The estimation of measured and indicated
resources involves greater uncertainty as to their existence and
economic feasibility than the estimation of proven and probable
reserves. U.S. investors are cautioned not to assume that measured
and indicated mineral resources will be converted into reserves.
The estimation of inferred resources involves far greater
uncertainty as to their existence and economic viability than the
estimation of other categories of resources. U.S. investors are
cautioned not to assume that estimates of inferred mineral
resources exist, are economically minable, or will be upgraded into
measured or indicated mineral resources. Under Canadian securities
laws, estimates of inferred mineral resources may not form the
basis of feasibility or other economic studies.
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. Accordingly, the
information contained in this press release may not be comparable
to similar information made public by U.S. companies that are not
subject NI 43-101.
Cautionary note regarding forward looking statements: This news
release contains forward-looking statements regarding future events
and Silver Bull's future results that are subject to the safe
harbors created under the U.S. Private Securities Litigation Reform
Act of 1995, the Securities Act of 1933, as amended (the
"Securities Act"), and the Securities Exchange Act of 1934, as
amended (the "Exchange Act"), and applicable Canadian securities
laws. Forward-looking statements include, among others, statements
regarding measured, indicated and inferred resource estimates, the
ability to use a "SART" process to reduce cyanide costs and recover
any zinc or copper, the ability to use coal from Coahuila to fuel
the kiln, the timing of the next resource update and completion of
a viable flow sheet, the ability to complete a preliminary economic
assessment, the timing of the completion of bottle roll tests on
the "Shallow Silver" and "Fonteriza" zones, the ability to
replicate the pyro-metallurgical recoveries on larger sample sizes
and the ability to delineate a zinc resource in the zinc
exploration target. These statements are based on current
expectations, estimates, forecasts, and projections about Silver
Bull's exploration projects, the industry in which Silver Bull
operates and the beliefs and assumptions of Silver Bull's
management. Words such as "expects," "anticipates," "targets,"
"goals," "projects," "intends," "plans," "believes," "seeks,"
"estimates," "continues," "may," variations of such words, and
similar expressions and references to future periods, are intended
to identify such forward-looking statements. Forward-looking
statements are subject to a number of assumptions, risks and
uncertainties, many of which are beyond our control, including such
factors as the results of exploration activities and whether the
results continue to support continued exploration activities,
unexpected variations in ore grade, types and metallurgy,
volatility and level of commodity prices, the availability of
sufficient future financing, and other matters discussed under the
caption "Risk Factors" in our Annual Report on Form 10-K for the
fiscal year ended October 31, 2011 and our other periodic and
current reports filed with the SEC and available on www.sec.gov and
with the Canadian securities commissions available on
www.sedar.com. Readers are cautioned that forward-looking
statements are not guarantees of future performance and that actual
results or developments may differ materially from those expressed
or implied in the forward-looking statements. Any forward-looking
statement made by us in this release is based only on information
currently available to us and speaks only as of the date on which
it is made. We undertake no obligation to publicly update any
forward-looking statement, whether written or oral, that may be
made from time to time, whether as a result of new information,
future developments or otherwise.
Contacts: Silver Bull Resources, Inc. Matt Hallaran Investor
Relations +1 604 336 8096info@silverbullresources.com
www.silverbullresources.com
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