Fronteer: Initial Northumberland Metallurgical Testing Reports Gold Recoveries Up to 87% for Sulfide Samples
March 01 2010 - 7:00AM
Marketwired
Fronteer (TSX: FRG)(NYSE Amex: FRG) announces today that initial
metallurgical test work at its 100% owned Northumberland gold
deposit, yields sulfide gold recoveries of up to 87% for samples
that are considered refractory in nature, and 89% for samples
considered to be transitional material. Recoveries of 93% are
observed on samples with a high cyanide (CN) solubility ratio.
These results indicate that Northumberland mineralization can be
processed with good recoveries using proven treatment methods.
"The outcomes from this test program are very encouraging and
will help us to define the economic potential of this project. We
are continuing with further metallurgical testing to optimize
recoveries and to minimize capital and operating costs," says Troy
Fierro, Fronteer Chief Operating Officer.
The results are the first from of a series of tests on the range
of mineralization styles found at Northumberland. Three composite
samples were taken from Fronteer's 2008 metallurgical core drilling
program. The composites were selected based upon cyanide solubility
ranges of low, medium and high. A bulk sample from Pad 4, which is
a historic leach pad known to contain sulfide mineralization, was
also submitted for testing.
The main objective of initial metallurgical testing was to
investigate the recovery characteristics of gold at various grind
sizes using Alkaline Pressure Oxidation (POX) technology followed
by standard carbon-in-leach (CIL) leaching.
The test work was performed by Dawson Metallurgical Lab (DML) of
Salt Lake City, Utah. Each composite was tested using a standard
set of conditions to characterize the variability of response to
each procedure. Standard bottle-roll and CIL tests conducted on
each composite determined that no significant preg-robbing organic
carbon was present. Thereafter, alkaline POX was followed by CIL to
extract gold and silver. Each composite was tested at three grind
sizes: 53 microns, 20 microns and fine grind ranging from 7.2-10.9
microns. The initial results indicate that a grinding to 20 microns
will yield very good recoveries. A second series of tests was
undertaken whereby a "polishing" regrind was conducted on the
20-micron samples and they were re-leached. This second stage
re-grind increased recoveries by an average of 5.3%, excluding the
caustic and high CN solubility tests.
Northumberland test results using Alkaline POX at a 20 Micron
Grind
--------------------------------------------------------------------------
% Au % Au
extraction extraction
Sample CN solubility (POX-CIL) (POX-Polish-CIL)
--------------------------------------------------------------------------
Low CN solubility 12.6% 80.6 87.2
--------------------------------------------------------------------------
Low CN solubility(i) 12.6% 85.1 86.6
--------------------------------------------------------------------------
Med CN solubility 38.0% 75.9 82.3
--------------------------------------------------------------------------
High CN solubility 86.1% 92.7 N/A
--------------------------------------------------------------------------
PAD 4 36.0% 86.3 89.1
--------------------------------------------------------------------------
(i) Caustic test: 5.0 kg NaOH added
In one test, 5.0 kg/t of caustic (NaOH) was added to the low CN
solubility sample, without a polishing re-grind. This test achieved
85.1% gold extraction, which is similar to other tests that
employed a polishing re-grind but did not use caustic. Follow-up
testing is currently underway using coarser primary grind sizes and
various chemical additions in an effort to reduce capital and
operating cost parameters, as well as increase gold and silver
recoveries.
Fronteer's ongoing metallurgical program is designed and managed
by Gary Simmons, of GL Simmons Consulting LLC. Mr. Simmons' work
experience includes metallurgical analyses of numerous mineralized
materials and ores for Newmont and Santa Fe Pacific Gold in Nevada
that are similar to Northumberland mineralization, including Twin
Creeks and deposits along north Carlin Trend.
CONCLUSION
This process currently demonstrates the potential to achieve
gold recoveries of up to 87% from non-preg-robbing sulfide
materials at Northumberland that are characterized by low cyanide
solubility. Samples that have medium cyanide solubility may achieve
recoveries of up to 89%, while high solubility material shows
potential to achieve recoveries in excess of the 90% range, using
the standard test conditions.
Northumberland, Sandman and Long Canyon comprise Fronteer's
future production platform based in Nevada. All three gold deposits
have high-grade gold starting at- or near-surface, are potentially
open-pit mineable and have encouraging production attributes.
Fronteer aims to build regional production by advancing these
projects sequentially over the near-term, and funding the company's
growth with low-risk of dilution. In the near-term, Fronteer
anticipates ongoing deposit growth to add significant gold ounces
to its ledger and pending results from a variety of development
activities to clearly define the economic strength of the company's
projects.
Gary Simmons, a Qualified Professional with the Mining and
Metallurgical Society of America and Fronteer consultant, is the
Qualified Person who has overseen the collection and verification
of the data for this release and has reviewed and approved this
release's content.
ABOUT FRONTEER
We intend to become a significant gold producer. Our solid
financial position and strengthened operational team give us the
ability to advance our key gold projects through to production. Our
future potential production platform includes our Long Canyon,
Sandman and Northumberland projects - all located in Nevada, one of
the friendliest gold-mining jurisdictions in the world.
Except for the statements of historical fact contained herein,
certain information presented constitutes "forward-looking
statements" within the meaning of the United States Private
Securities Litigation Reform Act of 1995 and Canadian securities
laws. Such forward-looking statements, including but not limited
to, those with respect to potential expansion of mineralization,
potential recovery rates, potential size of mineralized zone, and
size and timing of exploration and development programs, estimated
project capital and other project costs and the timing of
submission and receipt and availability of regulatory approvals
involve known and unknown risks, uncertainties and other factors
which may cause the actual results, performance or achievement of
Fronteer to be materially different from any future results,
performance or achievements expressed or implied by such
forward-looking statements. Such factors include, among others,
risks related to international operations and joint ventures, the
actual results of current exploration activities, conclusions of
economic evaluations, uncertainty in the estimation of mineral
resources, changes in project parameters as plans continue to be
refined, future prices of uranium, environmental risks and hazards,
increased infrastructure and/or operating costs, labour and
employment matters, and government regulation and permitting
requirements as well as those factors discussed in the section
entitled "Risk Factors" in Fronteer's Annual Information form and
Fronteer's latest Form 40-F on file with the United States
Securities and Exchange Commission in Washington, D.C. Although
Fronteer has attempted to identify important factors that could
cause actual results to differ materially, there may be other
factors that cause results not to be as anticipated, estimated or
intended. There can be no assurance that such statements will prove
to be accurate as actual results and future events could differ
materially from those anticipated in such statements. Fronteer
disclaims any intention or obligation to update or revise any
forward-looking statements, whether as a result of new information,
future events or otherwise, other than as required pursuant to
applicable securities laws. Accordingly, readers should not place
undue reliance on forward-looking statements.
NEWS RELEASE 10-09
Contacts: Fronteer Development Group Mark O'Dea, Ph.D, P.Geo
President and CEO 604-632-4677 or Toll Free 1-877-632-4677 Fronteer
Development Group Troy Fierro COO 604-632-4677 or Toll Free
1-877-632-4677 Fronteer Development Group Richard Moritz Director,
Investor Relations 604-632-4677 or Toll Free 1-877-632-4677
Fronteer Development Group Glen Edwards Director, Communications
604-632-4677 or Toll Free 1-877-632-4677 info@fronteergroup.com
www.fronteergroup.com
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