Excelsior Advances Prefeasibility & Provides Positive Metallurgy Test Results at Gunnison
September 10 2013 - 5:30AM
Marketwired Canada
Excelsior Mining Corp. (TSX VENTURE:MIN)(FRANKFURT:3XS)(OTCQX:EXMGF)
("Excelsior" or the "Company") is pleased to announce an update on the Company's
prefeasibility study as well as all the results from the most recent
metallurgical test program from its North Star deposit, part of Excelsior's
Gunnison Copper project, located in southeastern Arizona.
Prefeasibility Study Update
The Company has engaged M3 Engineering & Technology Corporation ("M3") of
Tucson, Arizona to support the Company in the completion of a prefeasibility
study on the Gunnison Copper project. M3 is a global full-service engineering
design firm that provides expertise in engineering and construction management
services. The firm has a long history of supporting base metal mining projects.
"M3's professionalism and direct experience with in-situ copper recovery
projects, including our Gunnison project, makes them the best choice to help
Excelsior complete the prefeasibility study; we look forward to releasing the
results later this year," said Stephen Twyerould, President and CEO of Excelsior
Mining.
Metallurgy Test Results at Gunnison Continue to Validate In-Situ Recovery Potential
A total of 13 submerged leach tests have been completed and the final results
are presented in the table below. Previously, the Company released the results
from five tests from the Lower Abrigo rock formation (see February 14, 2013 news
release:
http://www.excelsiormining.com/index.php/news/news-2013/392-metallurgy-tests-return-favourable-results-for-in-situ-recovery-at-gunnison);
these test results have been updated. In general, higher acid concentrations
generated faster recovery rates while longer leach times generated higher total
recoveries.
"Once again we have procured technical results that underscore the viability of
in-situ recovery at Gunnison," stated Stephen Twyerould. "These metallurgical
results, when combined with previous results, will be used for the preparation
of a prefeasibility study."
Submerged leach tests details
Submerged leach testing employs a protocol similar to column leach testing, but
modified to more closely reflect conditions during in-situ leaching. These tests
were designed to be repeatable, and to evaluate the response of mineralization
to in-situ leaching at different flow rates and acid concentrations.
The assay procedure for determining "acid soluble copper" does not typically
include copper present in the form of secondary copper sulfides which are
soluble under typical leaching conditions, including submerged leach tests.
Should the ore being tested contain some copper as secondary copper sulfides,
this copper will solubilize and as a consequent the calculated acid soluble
copper recovery may exceed 100 percent. This is the case in samples from the
Abrigo formation. Based on the sequential head assays, and given sufficient time
and acid concentration, it can be expected that copper recoveries could reach
105% to 115% of the acid soluble copper content for the Abrigo Formation and
100% for the Martin Formation.
The submerged leach tests were conducted by the independent laboratory, SGS
Metcon of Tucson, Arizona under the supervision of Dr. Ronald J. Roman, an
independent consultant who is a Qualified Person as defined by NI 43-101. Dr.
Roman has reviewed and approved the technical information disclosed in this news
release. Dr. Roman has verified the data underlying the test results by
designing the test procedure, supervising the test work, obtaining all the
analytical data over the life of the experiment and performing the calculations
presented below.
Table 1 - Results from submerged leach tests
----------------------------------------------------------------------------
Adj-
usted
Flow Acid
Rate Consu-
(2)(l/ Acid mption
Head h/ Content Days Estimated (5)
Grade Col- m (3)(g/l Leached Recovery lb/lb
(1)% umn (2)) acid) (4) % Cu
------------------ -----------------
Cu Cu Cu Cu
(total) (AS) SI (total) (AS)
----------------------------------------------------------------------------
Martin Formation
----------------------------------------------------------------------------
1.22 0.83 0.68 1 22 10 179 61 89 10.1
----------------------------------------------------------
5 then
15 then
2 22 to 20 179 70 98 13.0
----------------------------------------------------------
5 then
3 11 10 179 60 88 10.0
----------------------------------------------------------------------------
Upper / Middle Abrigo Formation
----------------------------------------------------------------------------
0.78 0.61 0.78 4 22 15 119 80 102 7.1
----------------------------------------------------------
5 37 10 119 76 98 5.7
----------------------------------------------------------
6 22 10 119 74 95 6.0
----------------------------------------------------------
7 22 5 119 63 80 4.7
----------------------------------------------------------
5 then
8 11 10 179 68 99 6.5
----------------------------------------------------------------------------
Lower Abrigo Formation
----------------------------------------------------------------------------
0.30 0.19 0.62 9 22 15 99 70 112 9.5
----------------------------------------------------------
10 37 10 76 68 109 6.3
----------------------------------------------------------
11 22 10 81 66 106 8.6
----------------------------------------------------------
12 22 5 99 57 92 4.8
----------------------------------------------------------
13 11 5 99 61 98 6.3
----------------------------------------------------------------------------
1. Calculated head grade: Cu (total) = total copper, Cu (AS) = acid soluble
copper, SI = solubility index Cu (AS) / Cu (total)
2. Flow rate: litres per hour of leach solution applied per cross-sectional
square metre
3. Acid Content: acid concentration of the leach solution in grams per
litre of free acid
4. Days leached includes periods of post leach rinsing
5. Adjusted Acid Consumption: test acid consumption in pounds of acid
consumed per pound of copper recovered adjusted by a factor of 0.5 to
compensate for overestimation due to the test protocol
The recovery/time curves for each formation can be found on the Excelsior
website at: http://www.excelsiormining.com/index.php/projects
To view the graphs accompanying this press release, click on the following link:
http://media3.marketwire.com/docs/graph910.pdf
Due to the nature of the copper oxide mineralization at North Star, combined
with standard metallurgical testing procedures on drill core, more of the
un-mineralized rock known as "gangue" is inadvertently exposed to the acid
solution than would be expected during normal in-situ mining conditions. This
overexposure results in inflated acid consumption rates from metallurgical
testing compared to those expected during actual in-situ operational conditions.
Previous acid consumption tests described in Excelsior's February 14, 2013 news
release indicated over estimation is in the order of 40% to 80%. As such, acid
consumption numbers presented in the table above represent test acid consumption
numbers multiplied by a factor of 0.5.
Further information concerning these metallurgical tests can be found on the
Excelsior website at: http://excelsiormining.com/index.php/projects.
Project Summary
The Gunnison Copper Project is located in a remote section of Cochise County in
southeastern Arizona. The focus of the project is the North Star deposit, which
currently has a total Measured and Indicated mineral resource of 3.21 billion
pounds of oxide copper (498 M tons at 0.32%) and an Inferred mineral resource of
0.83 billion pounds of oxide copper (156 M tons at 0.27%). This oxide mineral
resource has the potential to be mined using in-situ recovery methods. Mineral
resources which are not mineral reserves do not have demonstrated economic
viability.
About Excelsior
Excelsior is a mineral exploration and development company that is advancing the
Gunnison Copper Project. The Excelsior management team consists of experienced
professionals with proven track records of advancing mining projects into
production.
Excelsior's exploration work on the Gunnison Property is supervised by Dr.
Stephen Twyerould, Fellow of AUSIMM, President and CEO of Excelsior, and a
Qualified Person as defined by NI 43-101. Dr. Twyerould has reviewed and
approved the technical information disclosed in the "Project Summary" and "About
Excelsior" sections of this news release.
Further details about Excelsior can be found at: http://www.excelsiormining.com.
Further information about the Gunnison Copper Project can be found in the
technical report filed on SEDAR at www.sedar.com entitled: "Gunnison Copper
Project Preliminary Economic Assessment, NI 43-101 Technical Report" dated
November 18, 2011.
ON BEHALF OF THE EXCELSIOR BOARD
Stephen Twyerould, President & CEO
Cautionary Note Regarding Forward-Looking Information
This news release contains "forward-looking information" concerning anticipated
developments and events that may occur in the future. Forward looking
information contained in this news release includes, but is not limited to,
statements with respect to: (i) the estimation of inferred and indicated mineral
resources; (ii) the future implications of the metallurgical test results; (iii)
production from the Gunnison Project; (iv) the completion of a pre-feasibility
study; (v) expected acid consumption rates and; (vi) the ability to mine
Gunnison using in-situ recovery mining techniques are forward-looking
statements.
In certain cases, forward-looking information can be identified by the use of
words such as "plans", "expects" or "does not expect", "is expected", "budget",
"scheduled", "estimates", "forecasts", "intends", "anticipates" or "does not
anticipate", or "believes", or variations of such words and phrases or state
that certain actions, events or results "may", "could", "would", "might" or
"will be taken", "occur" or "be achieved" suggesting future outcomes, or other
expectations, beliefs, plans, objectives, assumptions, intentions or statements
about future events or performance. Forward-looking information contained in
this news release is based on certain factors and assumptions regarding, among
other things, the estimation of mineral resources, the realization of resource
estimates, copper and other metal prices, the timing and amount of future
exploration and development expenditures, the estimation of initial and
sustaining capital requirements, the estimation of labour and operating costs,
the availability of necessary financing and materials to continue to explore and
develop the Gunnison Project in the short and long-term, the progress of
exploration and development activities, the receipt of necessary regulatory
approvals, the completion of the environmental assessment process, the
estimation of insurance coverage, and assumptions with respect to currency
fluctuations, environmental risks, title disputes or claims, and other similar
matters. While the Company considers these assumptions to be reasonable based on
information currently available to it, they may prove to be incorrect.
Forward-looking information involves known and unknown risks, uncertainties and
other factors which 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 information. Such
factors include risks inherent in the exploration and development of mineral
deposits, including risks relating to changes in project parameters as plans
continue to be redefined including the possibility that mining operations may
not commence at the Gunnison Project, risks relating to variations in mineral
resources, grade or recovery rates resulting from current exploration and
development activities, risks relating to the ability to access infrastructure,
risks relating to changes in copper and other commodity prices and the worldwide
demand for and supply of copper and related products, risks related to increased
competition in the market for copper and related products and in the mining
industry generally, risks related to current global financial conditions,
uncertainties inherent in the estimation of mineral resources, access and supply
risks, reliance on key personnel, operational risks inherent in the conduct of
mining activities, including the risk of accidents, labour disputes, increases
in capital and operating costs and the risk of delays or increased costs that
might be encountered during the development process, regulatory risks, including
risks relating to the acquisition of the necessary licenses and permits,
financing, capitalization and liquidity risks, including the risk that the
financing necessary to fund the exploration and development activities at the
Gunnison Project may not be available on satisfactory terms, or at all, risks
related to disputes concerning property titles and interest, environmental risks
and the additional risks identified in the "Risk Factors" section of the
Company's reports and filings with applicable Canadian securities regulators.
Although the Company has attempted to identify important factors that could
cause actual actions, events or results to differ materially from those
described in forward-looking information, there may be other factors that cause
actions, events or results not to be as anticipated, estimated or intended.
Accordingly, readers should not place undue reliance on forward-looking
information. The forward-looking information is made as of the date of this news
release. Except as required by applicable securities laws, the Company does not
undertake any obligation to publicly update or revise any forward-looking
information.
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, and no securities
regulatory authority has either approved or disapproved of the contents of this
release.
FOR FURTHER INFORMATION PLEASE CONTACT:
Excelsior Mining Corp.
JJ Jennex
Vice President, Corporate Affairs
604-681-8030 x 240
info@excelsiormining.com
www.excelsiormining.com
Excelsior Mining Corp. (TSXV:MIN)
Historical Stock Chart
From May 2024 to Jun 2024
Excelsior Mining Corp. (TSXV:MIN)
Historical Stock Chart
From Jun 2023 to Jun 2024
