Benchmark Achieves 93% Gold Recovery and Confirms Strong Precious Metals Results Towards the Path to Gold and Silver Production
Benchmark Achieves 93% Gold Recovery and
Confirms Strong Precious Metals Results
Towards the Path to Gold and Silver
Production
Edmonton, Alberta--(Newsfile Corp. - April 27, 2022) -
Benchmark Metals Inc.
(TSXV: BNCH) (OTCQX:
BNCHF) (WKN: A2JM2X) (the "
Company
" or "
Benchmark
") - is pleased to announce advanced
metallurgical laboratory test results for the Company's 100% owned Lawyers gold-silver Project.
The
testwork has provided
gold leach recoveries averaging 93%, and silver recoveries of
approximately 65%
from the Amethyst Gold Breccia (AGB) and Cliffs Creek resources. The advanced
test work confirms a simple preliminary design using conventional whole rock cyanide leaching and
incorporating Merrill Crowe zinc precipitation to produce on-site gold and silver Dore.
The test work
builds a large data set throughout the main Amethyst Gold Breccia (AGB) and Cliffs Creek resource
areas, in addition to composites representing potentially the first years of mining in a conceptual mine
plan. The Lawyers Project is located in the historic mining region of the Golden Horseshoe, located in
north-central British Columbia (BC), Canada.
Jim Greig, President and Director, commented, "The results demonstrate exceptional gold recovery
from rocks utilizing a conventional and proven method that results in pouring gold and silver Dore bars.
Technical results and participation from miners like Yamana Gold in Benchmark Metals continues to
validate the potential to become Canada's next major gold and silver mine."
Ian Harris, VP Engineering, commented, "We are very encouraged by the metallurgical test results that
demonstrate robust recovery on a standard conceptual mining schedule and support using a
straightforward, proven, industry norm, processing flow sheet.
The growing data set is now incorporated
into our modelling and supportive of the evaluation of multiple mining scenarios for future feasibility level
evaluations."
The metallurgical program was advanced and coordinated by F. Wright Consulting Inc., under the
direction of Frank Wright, P. Eng.
Mr. Wright is an independent metallurgical consultant, with extensive
experience in precious and base metal process development.
He is the qualified person as defined by
National Instrument 43-101.
The supporting studies have been conducted by several globally recognized laboratories including:
ALS Laboratory - Kamloops, BC: for detailed comminution testing;
BV Mineral Process Laboratories - Richmond, BC: for optimization and variability gravity treatment
and bottle roll leaching studies;
FLSmidth Inc. - Salt Lake City, Utah: for leach response confirmation, gravity pre-treatment, and
filtration test work, and;
SGS Mineral Services - Lakefield, Ontario: for treatment circuit simulation for the leach process,
liquid/solid separation, and Merrill Crowe.
Various mineralogical studies have also been performed on AGB and Cliffs Creek samples that indicate
the gold is primarily present as fine native particles.
Depending on the sample specimen, the silver
occurs predominantly as acanathite (Ag
2
S), or electrum, often as coarser particles of 200 microns or
greater, although it can be fine grained as well.
To a lesser extent native silver is present.
*
Gold equivalent (AuEq) calculated using 80:1 silver to gold ratio.
Image #1 - Core sample from the Cliff Creek Deposit representing the largest mineral resource
area
Selected drill core from drill hole 21CCDD085, containing electrum and native silver grading
77.9
grams per tonne (g/t) gold
and
1,675 g/t silver
or
98.84 g/t gold equivalent
(*AuEq).
To view an enhanced version of Image #1, please visit:
https://orders.newsfilecorp.com/files/6169/121774_image1.jpg
Metallurgical Testing Results
The recent laboratory studies suggest processing by grinding to a targeted feed particle size 80%
passing (P
80
) range of 106 to 125 microns, incorporating gravity pretreatment by centrifugal
concentration, followed by conventional cyanide leaching of the gravity tailing.
These moderate operating
conditions provide excellent gold recoveries, that consistently exceed 90%. The majority of the gold is
yielded within 24 hours of leach retention time.
More intensive treatment procedures provide minimal
improvement to the overall gold recovery.
As is typical for this type of mineralization the silver leach dissolution is more challenged, averaging
approximately 65%.
Generally higher silver recovery occurs in the Cliffs Creek Zone, as compared to
AGB.
The silver recovery benefited from an additional 12 hours of leach retention time, along with
elevated sodium cyanide (NaCN) addition and increased pH (with lime).
Additional more aggressive
procedures such as use of lead nitrate, oxygen, finer grinding, further lixiviant, and elevated caustic can
offer some limited further improvement to silver recovery.
However, the more aggressive treatment
procedures were not deemed to be economically beneficial at this time.
Further optimization of silver
recovery will be undertaken in the future as mill head grade and metal pricing accuracy improve towards
more detailed economic evaluation.
These reported test results are additional to prior optimization testing, and to preliminary data previously
reported in June 2021. The following Table provides a summary of the most recent bottle roll data
obtained under ambient conditions, with 36 hours of leach retention time at 40 wt.% solids, and pH~11.
This recently completed laboratory program consists of a further 40 variability samples conducted on
AGB zone, and 25 variability samples from the Cliffs Creek zone.
The variability samples originate from
drill core assay rejects composited in length to each represent potential mining bench heights of ~10 m.
Separately included in the Table are Year 1 to Year 5 annual composites that were blended based on
the most recent conceptual mining schedule.
Table 1: Summary Table of Variability Test Results - Gold and Silver Leach Recovery
To view an enhanced version of Table 1, please visit:
https://orders.newsfilecorp.com/files/6169/121774_table1.jpg
The results confirm the initial metallurgical evaluation that with modest operating conditions a positive
process response is expected from both the principal mineral zones of the Lawyers property.
This is
especially true for gold, which is the primary metal value, and shows recovery in the low to mid ninety
percent range for samples obtained spatially and at depth to well represent the known resource.
The
initial metallurgical data has been incorporated into the preliminary economic assessment anticipated
for issuing near the end of the second quarter of 2022.
Following this, the current data, along with further
evaluation to be undertaken will be used in the upcoming Feasibility Study.
The technical content of this news release has been reviewed and approved by Michael Dufresne, M.Sc,
P.Geol., P.Geo., a qualified person as defined by National Instrument 43-101.
About Benchmark Metals
Benchmark Metals Inc. is a Canadian based gold and silver company advancing its 100% owned
Lawyer's Gold-Silver Project located in the prolific Golden Horseshoe of northern British Columbia,
Canada. The Project consists of three mineralized deposits that remain open for expansion, in addition
to +20 new target areas along the 20 kilometre trend. The Company trades on the TSX Venture
Exchange in Canada, the OTCQX Best Market in the United States, and the Tradegate Exchange in
Europe. Benchmark is managed by proven resource sector professionals, who have a track record of
advancing exploration projects from grassroots scenarios through to production.
www.metalsgroup.com
ON BEHALF OF THE BOARD OF DIRECTORS
s/ "John Williamson"
John Williamson
, Chief Executive Officer
For further information, please contact:
Jim Greig
Email:
Telephone: +1 604 260 6977
NEITHER 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 certain "forward-looking statements". Forward-looking statements
involve known and unknown risks, uncertainties, assumptions and other factors that may cause the actual
results, performance or achievements of the Company to be materially different from any future results,
performance or achievements expressed or implied by the forward-looking statements. Any forward-
looking statement speaks only as of the date of this news release and, except as may be required by
applicable securities laws, the Company disclaims any intent or obligation to update any forward-looking
statement, whether as a result of new information, future events or results or otherwise.
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