Searchlight Minerals Corp. Successfully Completes Pilot Autoclave Test Producing 0.42 Opt Gold Into Solution; Results Confirm...
July 08 2013 - 7:00AM
Marketwired
Searchlight Minerals Corp. (OTCBB: SRCH) ("Searchlight" or the
"Company") today announced that it has successfully run its pilot
autoclave on slag material taken from the Clarkdale Slag Project
and furthermore, the results of the latest test confirmed gold in
hand from fire assay.
Test Results
The ninth and latest pilot autoclave test demonstrated that 0.42
ounces per ton ("opt") gold was leached into solution from the slag
sample containing 0.48 opt gold, which represents an estimated gold
recovery of 87.5%. While past test work had relied upon 'wet
chemistry' electronic determination, these latest results were
determined by analyzing gold metal extracted by standard fire assay
techniques.
Solution values were determined by evaporating the pregnant
leach solution ("PLS") and fire assaying the residual solids to
produce a gold bead in hand. Likewise, the finely ground slag going
into the large pilot autoclave and the leached residue after the
test were also fire assayed and the resultant gold beads were used
to calculate gold grades and leach efficiency. This is the second
autoclave test that has verified the gold grade of the slag by fire
assay. Electrowinning tests are currently underway to recover gold
as metal from the PLS.
Background
Since December 2012, in an effort to demonstrate the economic
viability of the Clarkdale Slag Project, the Company has been
operating its large batch pilot autoclave. The 240-gallon
(approximately 900 liter) autoclave consists of a titanium shell
stirred reactor and all of the control and support systems.
A total of nine tests have been conducted in the pilot
autoclave. The initial tests were designed to examine the
structural integrity and functionality of the autoclave, its
components, control and support systems. Subsequent tests were
designed in an effort to mimic the mechanical and chemical
operating conditions achieved with previous tests in the 6-liter
bench autoclave, which yielded approximately 0.4 to 0.5 opt of gold
in solution.
As the tests progressed, several mechanical and chemical issues
were identified which indicated that the pilot autoclave was
operating under less than optimum conditions, resulting in low gold
extraction values. As these issues were identified, modifications
were undertaken to the autoclave in order to help achieve the
desired operating conditions. Significant delays occurred due to
specialty alloy parts having to be ordered and in some cases custom
made. During this time, additional bench-scale autoclave tests were
performed in order to modify and optimize the chlorine chemistry
for the pilot autoclave.
James Murray, the Project Manager of the Clarkdale Slag Project,
noted "Because of our recent modifications to the mechanical and
chemical operating conditions of the pilot autoclave, we were able,
for the first time, to closely replicate the conditions of the
bench-scale autoclave tests that were successful in achieving a
high level of gold extraction from the slag material." Mr. Murray
continued, "I attribute the breakthrough to being able to maintain
sufficiently high oxidizing conditions via optimization of the
chlorine chemistry and the operating conditions of the large pilot
autoclave. This was achieved by the addition of supplementary
heating capacity to the autoclave as well as a high pressure
corrosion resistant pump to allow the addition of highly oxidizing
chlorine compounds during the test. Additionally, there were
seventeen 6 liter bench autoclave tests performed to modify and
optimize the chlorine chemistry for the pilot autoclave. The final
step in validating the technical and commercial feasibility of the
autoclave process is the recovery of the gold from the PLS.
Electrowinning tests are currently underway to recover gold as
metal from the PLS. The large pilot autoclave tests provide
sufficient volume of PLS for operating a pilot scale electrowinning
cell."
"While testing has taken longer than originally anticipated due
to unforeseen issues," stated Martin Oring, the Company's CEO, "we
have gathered a tremendous amount of data from our tests and
believe that we understand the conditions under which we must
operate in order to achieve a high level of gold extraction from
our slag material. We intend to continue our testing in an effort
to consistently extract high levels of gold into solution and
concurrently, we will continue with our PLS gold extraction tests
in an effort to demonstrate our ability to complete the circuit and
to produce physical gold. Once we are repetitively able to achieve
this, we believe we will be in a position to embark on our bankable
feasibility study which will demonstrate the economic viability of
the Clarkdale Slag Project."
About Searchlight Minerals Corp.
Searchlight Minerals Corp. is an exploration stage company
engaged in the acquisition and exploration of mineral properties
and slag reprocessing projects. The Company holds interests in two
mineral projects: (i) the Clarkdale Slag Project, located in
Clarkdale, Arizona, which is a reclamation project to recover
precious and base metals from the reprocessing of slag produced
from the smelting of copper ore mined at the United Verde Copper
Mine in Jerome, Arizona; and (ii) the Searchlight Gold Project,
which involves exploration for precious metals on mining claims
near Searchlight, Nevada. The Clarkdale Slag Project is the more
advanced of two ongoing projects that the Company is pursuing. The
Searchlight Gold Project is an early-stage gold exploration
endeavor on 3,200 acres located approximately 50 miles south of Las
Vegas, Nevada.
Searchlight Minerals Corp. is headquartered in Henderson,
Nevada, and its common stock is listed on the OTC Bulletin Board
under the symbol "SRCH." Additional information is available on the
Company's website at www.searchlightminerals.com and in the
Company's filings with the U.S. Securities and Exchange
Commission.
Forward-Looking Statements
This Press Release may contain, in addition to historical
information, forward-looking statements. Statements in this Press
Release that are forward-looking statements are subject to various
risks and uncertainties concerning the specific factors disclosed
under the heading "Risk Factors" in the Company's periodic filings
with the Commission. When used in this Press Release in discussing
the recent developments on the Project, including, without
limitation, the resolution of certain issues relating to the
operation of the production module, the words such as "believe,"
"could," "may," "expect" and similar expressions are
forward-looking statements. The risk factors that could cause
actual results to differ from these forward-looking statements
include, but are not restricted to technical issues on the Project
that may affect the production module and its primary process
components, challenges in moving from pilot plant scale to
production scale, the risk that actual recoveries of base and
precious metals or other minerals re-processed from the slag
material at the Clarkdale site will not be economically feasible,
uncertainty of estimates of mineralized material, operational risk,
the Company's limited operating history, uncertainties about the
availability of additional financing, geological or mechanical
difficulties affecting the Company's planned mineral recovery
programs, the risk that actual capital costs, operating costs and
economic returns may differ significantly from the Company's
estimates and uncertainty whether the results from the Company's
feasibility studies are not sufficiently positive for the Company
to proceed with the construction of its processing facility,
operational risk, the impact of governmental and environmental
regulation, financial risk, currency risk volatility in the prices
of precious metals and other statements that are not historical
facts as disclosed under the heading "Risk Factors" in the
Company's periodic filings with securities regulators in the United
States. Consequently, risk factors including, but not limited to
the aforementioned, may result in significant delays to the
projected or anticipated production target dates.
Contact Information: RJ Falkner & Company, Inc. Investor
Relations Counsel (800) 377-9893 Email Contact
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