Gentor Resources receives excellent results from initial metallurgical test work on high-grade Massive Sulphide from the Mahab
April 24 2012 - 8:00AM
PR Newswire (Canada)
A composite drill core sample of primary massive sulphides from
Mahab 4 with a head grade of 9.77% copper was successfully upgraded
by means of standard flotation conditions to produce marketable
concentrate grades of 20-27% copper at recoveries of 90-94% copper.
TORONTO, April 24, 2012 /CNW/ - Gentor Resources Inc. ("Gentor")
(OTCQB: GNTOF) and its Omani partner Al Fairuz Mining Company LLC
are pleased to announce the results of initial flotation testwork
on its flagship Mahab 4 Cyprus-type copper discovery in Block 5.
Gentor commissioned Wardell Armstrong International based in
Cornwall UK to provide a programme of scoping flotation testwork
initially on a composite sample of high grade massive sulphide
copper mineralisation from its recently drill evaluated Mahab 4
deposit. Testwork Summary Standard testwork using nominal
parameters for Oman massive sulphides was applied as a base case to
a combined massive sulphide-semi-massive sulphide sample grading
9.77% copper, producing a copper recovery of 85% to an acceptable
20.2% copper concentrate. Follow-up rougher tests summarised in
Figure 1 below - using the base case but varying the initial
conditions - produced a variety of higher grade concentrates with
lower recoveries. However, finer grinding applied to allow 80%
passing 40 microns released more copper tied up within pyrite
grains to give a +90% copper recovery. Subsequent cleaner tests
summarised in Figure 2 below have shown that it is possible to
achieve either: -- a circa 20.0% copper grade to 94% recovery from
roughing alone; or -- a circa 27.5% copper grade to 90% recovery
from roughing + one stage of cleaning. Dependent on the copper
grade the concentrate contained 30-50% of the sulphide ore
content. The efficiency of the cleaner process determined
that regrinding options appear to add little benefit. This test
work therefore suggests that a relatively simple process using
standard techniques and reagents is applicable for the Mahab 4
massive sulphides. Gentor is now preparing a wider selection of ore
type core samples including stringer zone and lower grade massive
sulphides in order to determine standard testwork treatment
parameters for the range of important bulk ore types at Mahab 4.
Gentor's President & CEO Dr. Peter Ruxton commented: "Gentor is
very pleased with these encouraging initial metallurgical tests
that confirm our expectations that the high-grade massive sulphides
at Mahab 4 will be readily treatable to produce a clean economic
concentrate. We have now approved further feasibility test
work on a range of typical Mahab 4 ore types to obtain a
comprehensive understanding of flotation conditions for this
deposit." Test Work Program In order to maximise the efficiency of
the preliminary program the experiences and parameters of flotation
treatment of various Oman Cyprus-type VMS deposits was utilised and
incorporated into this phase of test work to provide initial test
conditions. In addition, a detailed mineralogical examination of
the composite sample was undertaken in order to determine factors
such as the main sulphide and gangue minerals present, their
liberation sizes and degrees of alteration. The massive sulphide
ore type at Mahab 4 has a simple mineralogy comprising dominant
early brecciated pyrite, partly replaced at all size levels by
chalcopyrite and minor sphalerite; in a silica rich gangue. This
enabled identification of the most appropriate grind size, for each
sample prior to undertaking additional flotation tests in order to
optimise reagent conditions including defining collector type and
dosage, flotation pH, and circuit configuration including number
and length of cleaning stages. Resultant base case conditions
established included: -- Grinding D80: 60µm -- pH 11.5 -- 200g/t
Cytec A238 collector The final program recently completed involved
ten rougher tests and five cleaner tests. Rougher Results FT1 the
first test for the MS head assay of 9.77% Cu (0.069% Cu( (sol))),
46.96% S (0.29% S( (sol))), and 0.30 mg/kg Au gave an excellent
rougher flotation response of 85% recovery to 20.2% Cu concentrate.
This provided a strong basis from which to move forward with
further testwork to investigate the effect of pH, collector dosage
and primary grind size on flotation performance and subsequently
the collector type efficiency. These further tests showed: -- FT2 -
Increasing flotation pH from 11.5 to 12.0 resulted in a reduction
in copper recovery after 10 minutes of flotation from 83.7% to
77.8%. The grade of concentrate was, however, approximately 2%
higher in the concentrate suggesting that the increased pH was
depressing chalcopyrite that was associated with pyrite. -- FT3 -
Increasing the amount of collector added from a total of 200g/t
(FT1) to 300g/t resulted in an increase in copper recovery from
84.9% to 94.2% after 10 minutes. The increase in recovery did
however result in a reduction in the grade of concentrate of
approximately 3.2% to 17.1% Cu. -- FT4 - Reducing the primary grind
size from 80% passing 60µm to 80% passing 40µm resulted in an
increase in copper recovery of 8.1%, when compared with FT1, to
93.1%. The results also showed that despite the increase in
recovery, there was no detrimental effect on concentrate grade with
levels of circa 20.5% Cu being maintained. Based on these results,
it would appear that a finer primary grind size is of more benefit
for increased recovery than increased collector dosage. Therefore
the second stage of testwork involved four rougher flotation tests
using this finer grind size to again look at the effect of pH along
with alternative copper collectors on flotation performance. Test
conditions and results are summarised as follows; -- FT5 - Repeat
of test 4 (200g/t A238 at a grind size of 80% passing 40µm) but
with initial flotation pH increased from 11.5 to 12.0. Results
showed that the increase in pH increased the maximum grade of
concentrate that was achievable, however, there was no improvement
in overall recovery. -- FT6 - Repeat of test 4 but with the Cytec
Aero 238 collector substituted for SIPX. Dosage levels were
maintained. The results showed that the alternative collector
provided the highest copper recovery observed to date of 97.2%,
however, the grade of concentrate was just 12.6% Cu. When the grade
of concentrate was increased to 20% Cu, recovery fell to levels
which were below that which could be achieved using the previous
selective collector. -- FT7 - Repeat of test 6 but with collector
dosage reduced to 75% of original level. Results showed that the
test achieved higher concentrate grades than test 6 although
recovery levels were lower. -- FT8 - Repeat of test 4 but with
primary grind size reduced from 80% passing 40µ to 80% passing
30µm. The results showed that the reduction in primary grind size
resulted in a circa 2% increase in copper recovery at 'lower'
grades (circa 22-23% Cu) but that as concentrate grade increased
recoveries fell to levels achieved at coarser grind sizes. Based on
these results, it would appear that the best conditions identified
to date are those of the test 4 regime as seen in Figure 1.
Consequently, two additional tests were performed based on this
regime but with the flotation pH reduced from 11.5 to 10.5. The
first test (FT9) was performed using Aero 238 whilst the second
(FT10) was performed using SIPX. Based on the responses shown in
Figure 1 it would seem that the lower pH produces a less economical
result and the Aero 238 performs much better than the SIPX,
therefore overall the test 4 conditions appear close to optimal for
this material. Cleaner Results A program of five cleaner tests were
conducted that confirmed minimal treatment with standard conditions
and reagents was required to produce an acceptable range of
concentrates ranging from 20-27% Cu with commensurate high copper
recoveries of 90-94%. Furthermore, given that these results show
that only one stage of cleaning is required, it was considered
unnecessary to proceed with the proposed locked cycle testwork
which might be more appropriate for subsequent evaluation of lower
grade MS ores. A final report on this work is not yet available
however a summary of testwork results is presented in Figure 2.
This indicates that tests FC2 and FC5 appear to optimise the copper
recovery above 90% with a minimum concentrate value of 20% Cu, and
that finer grinding in FC5 provides up to 2% better recovery in
concentrates up to 27% Cu, but at higher grades does not improve
performance and is of marginal value. Therefore it is suggested no
regrind may be necessary for this high-grade material. Locality
plans of the Oman concessions including the Mahab 4 deposit are
found on the Company's
website:http://www.gentorresources.com/s/NewsReleases.asp?ReportID=517002
Qualified Person The results disclosed in this press release have
been reviewed, verified (including sampling, analytical and test
data) and compiled by senior geologists under the direction of Dr.
Peter Ruxton who is a Professional Member of the Institute of
Materials, Minerals and Mining (I.M.M.M.), the Company's President
and Chief Executive Officer and a "qualified person" (as such term
is defined in Canadian National Instrument 43-101 as promulgated by
the Canadian Securities Administrators). Technical Report
Additional information with respect to the Company's Omani
properties is contained in the technical report prepared by Venmyn
Rand (Pty) Ltd, dated December 31, 2010 and entitled "National
Instrument 43-101 Independent Technical Report on Block 5 and Block
6 Copper Projects, Semail Ophiolite Belt, Sultanate of Oman held by
Gentor Resources, Inc." A copy of this report can be obtained
from SEDAR at www.sedar.com. About Gentor Gentor is a mineral
exploration company whose projects include copper and gold
properties in the Sultanate of Oman and a
molybdenum-tungsten-silver property in East Central Idaho,
U.S. The Company's strategy is to create shareholder value by
developing highly prospective mineral properties around the globe,
with current focus in the Sultanate of Oman. In Oman, Gentor
is partnered with Al Fairuz Mining Company LLC on its Block 5
exploration tenement and Al Zuhra Mining Company LLC on Block 6.
Cautionary Notes Forward-Looking Information: This press
release contains forward-looking information. All statements,
other than statements of historical fact, that address activities,
events or developments that the Company believes, expects or
anticipates will or may occur in the future (including, without
limitation, statements regarding metallurgical testwork and other
exploration results, potential mineral resources, potential
mineralization and the Company's exploration and development plans)
are forward-looking information. This forward-looking
information reflects the current expectations or beliefs of the
Company based on information currently available to the
Company. Forward-looking information is subject to a number
of risks and uncertainties that may cause the actual results of the
Company to differ materially from those discussed in the
forward-looking information, and even if such actual results are
realized or substantially realized, there can be no assurance that
they will have the expected consequences to, or effects on the
Company. Factors that could cause actual results or events to
differ materially from current expectations include, among other
things, copper recoveries being less than those indicated by the
metallurgical testwork carried out to date (there can be no
assurance that copper recoveries in small scale laboratory tests
will be duplicated in large tests under on-site conditions or
during production); risks related to the exploration stage of the
Company's properties, the possibility that future exploration
results will not be consistent with the Company's expectations,
changes in world copper or gold markets and equity markets,
political developments in Oman, uncertainties relating to the
availability and costs of financing needed in the future, the
uncertainties involved in interpreting exploration results and
other geological data and the other risks involved in the mineral
exploration business. Forward-looking information speaks only
as of the date on which it is provided and, except as may be
required by applicable securities laws, the Company disclaims any
intent or obligation to update any forward-looking information,
whether as a result of new information, future events or results or
otherwise. Although the Company believes that the assumptions
inherent in the forward-looking information are reasonable,
forward-looking information is not a guarantee of future
performance and accordingly undue reliance should not be put on
such information due to the inherent uncertainty therein. The
United States Securities and Exchange Commission (the "SEC")
permits mining companies, in their filings with the SEC, to
disclose only those mineral deposits that a company can
economically and legally extract or produce. U.S. investors are
cautioned not to assume that any disclosure of mineralization
contained in this press release is economically or legally
mineable. U.S. investors are urged to closely consider all of
the disclosures in the Company's reports filed pursuant to the
United States Securities Exchange Act of 1934 which may be secured
from the Company, or from the SEC's website at
http://www.sec.gov/edgar.html. 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. SOURCE Gentor Resources
Inc. Image with caption: "Figure 1. Summary of Rougher Testwork
Results (CNW Group/Gentor Resources Inc.)". Image available at:
http://photos.newswire.ca/images/download/20120424_C8386_PHOTO_EN_12649.jpg
Image with caption: "Figure 2. Summary of Cleaner Testwork Results
(CNW Group/Gentor Resources Inc.)". Image available at:
http://photos.newswire.ca/images/download/20120424_C8386_PHOTO_EN_12648.jpg
Gentor Resources Inc. CONTACT: please visit our website at
www.gentorresources.com, or contact:Dr.Peter Ruxton, President
& CEO, United Kingdom Tel: + 44 (0) 7786111103; or Arnold T.
Kondrat, Executive Vice President, Toronto,Ontario, Tel: + 1 (416)
366 2221 or + 1 (800) 714 7938.
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