Thundermin and Cornerstone Report Excellent Metallurgical Results from Scoping Level Test Work Undertaken on Core Samples from t
October 19 2010 - 8:00AM
Marketwired Canada
Thundermin Resources Inc. ("Thundermin") (TSX:THR) and 50% joint venture partner
Cornerstone Resources Inc. ("Cornerstone") (TSX VENTURE:CGP) are pleased to
announce that excellent metallurgical results have been obtained from scoping
level test work undertaken on core samples from the Little Deer Copper Deposit
("Deposit") which is located approximately 10 km north of Springdale in
north-central Newfoundland.
HIGHLIGHTS
-- Production of a saleable, high grade copper concentrate grading over 28%
copper with over 97% copper recovery in locked cycle tests
-- Copper concentrates free of any deleterious elements
-- Copper recovered employing a simple rougher-cleaner flowsheet using a
common xanthate collector
-- Copper mineralization of medium hardness with Bond ball mill work index
of 14.6 kilowatt hours per tonne ("kWh/t")
-- Fresh and aged tailings decant solutions well within Canadian Metal
Mining Effluent Regulations ("MMER") limits and non-lethal designations
for MMER aquatic toxicology tests
Work Summary
SGS Lakefield Research ("Lakefield") of Lakefield, Ontario, an ISO 17025:2005
accredited company, was retained by Thundermin and Cornerstone to undertake a
scoping level metallurgical test program on copper mineralization from the
Deposit accompanied by basic environmental characterization of the flotation
tailings produced from the metallurgical test program.
The metallurgical test program consisted of two main components: 1) sample
characterization including head sample chemical analysis, quantitative
evaluation of materials by QEMSCAN(TM) analysis, and Bond ball mill grindability
tests; and 2) flotation testing including rougher and cleaner testing, locked
cycle testing and detailed concentrate chemical analysis. The environmental test
program consisted of: 1) inductively coupled plasma-optical emission
spectroscopy/mass spectroscopy ("ICP-OES/MS") elemental analysis; 2) shake flask
extraction ("SFE") testing; 3) modified acid base accounting ("ABA"); 4) net
acid generation ("NAG") testing; 5) ICP-OES/MS analysis of the fresh and aged
tailings decant solutions; and 6) single concentration acute lethality testing
of effluent on MMER aquatic test species (Daphnia Magna and Rainbow Trout).
Sample Preparation and Head Grade
Approximately 200 kilograms ("kg") of crushed reject core sample was shipped to
Lakefield in plastic pails. This sample was selected from six drill holes
located throughout the Deposit and was designed to approximate, as closely as
possible, the anticipated average copper grade for the Deposit. At Lakefield,
the sample was combined and blended into one 200 kg composite sample. Ninety
(90) kg was riffle split from this sample for metallurgical testing and the
remainder was stored in a freezer. Ten (10) kg of the sample was riffled out for
a Bond ball mill work index hardness test. The remaining 80 kg was stage-
crushed to -10 mesh and rotary split into 2 kg test charges for flotation
testing. All materials were stored frozen until subjected to testing.
A 2 kg test charge sample was submitted for a range of chemical analysis. The
head grade of the sample was 2.43% copper, 0.034% cobalt, 0.03 g/t Au, 19.1%
iron and 5.99% sulphur.
Grindability Test Results
A standard Bond ball mill grindability test was completed at a closing sieve
size of 80 mesh. The Bond mill work index was measured at 14.6 kWh/t which is
considered to be of medium hardness based on Lakefield's extensive work index
database.
Flotation Test Results
Flotation test results revealed that the copper mineralization at Little Deer
can be recovered easily using a simple rougher-cleaner flowsheet with a common
xanthate collector at a pH of 9 using lime as the modifier. An analysis of the
liberation characteristics of the chalcopyrite determined that the primary grind
needs to be in the range of 80% passing 150 microns, with a regrind in the range
of 80% passing 30- 40 microns likely necessary.
Results of two locked cycle tests completed on samples of the Little Deer copper
mineralization are presented below in Table 1. Test LCT-1 differed from LCT-2
mainly with respect to primary grind size, with LCT-1 completed at a primary
grind P80 of 160 um versus LCT-2, which was at a P80 of 100 um. Both tests
achieved approximately 97% copper recovery into a saleable concentrate grading
28% copper.
Table 1. Locked Cycle Test Results
----------------------------------------------------------------------------
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Assays Distribution
-----------------------------------
Test Grind Product Weight
No. Size % % Cu % S % Co % Cu % S % Co
----------------------------------------------------------------------------
LCT-1 1 degrees Cu 3rd Cleaner
- 162um Conc 8.3 28.0 34.3 0.065 96.7 49.0 20.8
2 degrees Cu 1st Cl Scav
- 34um Tail 11.6 0.28 14.2 0.078 1.4 28.1 34.9
Cu Rougher Tail 80.1 0.059 1.67 0.014 2.0 22.9 44.3
Head (calc.) 100.0 2.41 5.82 0.026 100.0 100.0 100.0
----------------------------------------------------------------------------
LCT-2 1 degrees Cu 3rd Cleaner
- 96um Conc 8.2 28.3 34.4 0.061 97.2 48.9 17.0
2 degrees Cu 1st Cl Scav
- 32um Tail 10.6 0.33 16.0 0.107 1.5 29.3 38.7
Cu Rougher Tail 81.1 0.038 1.56 0.016 1.3 21.8 44.2
Head (calc.) 100.0 2.40 5.80 0.029 100.0 100.0 100.0
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Environmental Test Results
The purpose of the environmental test program was to assess the geochemical,
acid rock drainage ("ARD"), aquatic toxicology and contaminant mobility
potential associated with the Little Deer flotation tailings materials over
time. The ICP-OES/MS strong acid digest elemental analysis indicated that the
tailings sample was predominantly comprised of silica and iron with moderate to
minor amounts of alumina, magnesium and calcium. Analysis of the shake flask
extraction leachate reported a slightly alkaline final pH value and all MMER
controlled parameters at concentrations well within the designated limits. ABA
indicated that the tailings sample was potentially acid generating and NAG
testing confirmed the acid generating nature of the tailings sample. Analysis of
the fresh and aged tailings decant solutions reported all controlled parameters
at concentrations well within MMER limits and acute lethality testing of the
Decant Day 28 solution resulted in non-lethal designations for both Daphnia
Magna and Rainbow Trout.
Conclusions
The results of a scoping level metallurgical test program on a representative
composite sample of copper mineralization from the Deposit indicate that a
saleable, high grade concentrate grading 28% copper can be achieved with
approximately 97% copper recovery.
The use of a simple rougher-cleaner flowsheet, a common xanthate collector, pH
control with lime and a relatively course primary grind for copper liberation
from mineralization of medium hardness suggest that the operating costs should
fall into the low range for any metallurgical plant constructed to treat the
Little Deer mineralization.
Mineral Resource Estimate
On October 13, 2010, Thundermin and Cornerstone reported an updated National
Instrument 43-101 ("NI 43-101") mineral resource estimate for the Deposit
comprising Indicated Mineral Resources of 1,150,500 tonnes at an average grade
of 2.8% Cu within the Little Deer Zone and Inferred Mineral Resources of
2,355,500 tonnes at an average grade of 2.1% Cu within the Little Deer and
Footwall Zones (see news release dated October 13, 2010).
Based on diamond drilling results to date, the Deposit is interpreted to consist
of two main copper-bearing zones, the Little Deer Zone and the Footwall Zone
with the Footwall Zone occurring mainly west of, and from 50 to 75 m below, the
Little Deer Zone. A number of additional copper-bearing zones have also been
intersected in the footwall of these two zones, but their extent and
significance are unknown at the present time. The Deposit has been intersected
over a strike length of approximately 1,050 m and to a vertical depth of
approximately 1,000 m. The overall Deposit remains open along strike to the east
and west, up dip and at depth and the potential exists for the discovery of
additional mineral resources in all areas.
Little Deer Joint Venture
Thundermin, the operator, and Cornerstone have the option, on a 50/50 basis to
earn a 100% interest in the Deposit and adjacent property from Weyburn
Investments Ltd. Thundermin, under its joint venture agreement with Cornerstone,
has the right to increase its interest in the Little Deer property to 75% by
completing a feasibility study and by arranging 100% of the necessary bank
financing required to place the property into commercial production. Details on
the Deposit and the terms of the agreement with Weyburn can be found in numerous
news releases and on Thundermin's and Cornerstone's respective websites and on
SEDAR.
Qualified Persons
Mr. Dan Imeson, M.Sc., Manager, Mineral Processing for Lakefield supervised the
metallurgical test program on the Little Deer copper mineralization and Ms.
Barbara A. Bowman, Senior Technologist, Environmental Testing and Mr. Robert J.
Caldwell, Group Leader, Environmental Testing for Lakefield supervised the basic
environmental characterization of the flotation tailings produced during the
scoping level flotation testing of the Little Deer copper mineralization. Mr.
Imeson, Ms. Bowman and Mr. Caldwell have all reviewed the contents of this news
release for accuracy with respect to the metallurgical work done at Lakefield.
Mr. Klaus Konigsmann, P. Eng., Thundermin's and Cornerstone's metallurgical
consultant and independent Qualified Person ("Q.P.") in accordance with NI
43-101, has also reviewed the contents of this news release for accuracy with
respect to the metallurgical work done at Lakefield. The mineral resource
estimate for the Deposit was prepared by Mr. Reno Pressacco, M.Sc.(A), P.Geo.,
Senior Geologist for Scott Wilson Roscoe Postle Associates Inc. of Toronto,
Ontario, an independent Q.P. in accordance with NI 43-101. Mr. Pressacco has
reviewed the contents of this release for accuracy with respect to the mineral
resource estimate.
About Thundermin
Thundermin is a Canadian-based mineral exploration company focused on the
exploration for and the discovery of economically viable base metal and gold
deposits in Canada. Thundermin has an interest in, or the right to earn an
interest in 11 base metal and gold properties in Canada. Thundermin also has
royalty interests in a further 28 base metal and gold properties located in
Manitoba, Saskatchewan, British Columbia and Quebec, the most significant being
a 2.5% net smelter return royalty in the Pelletier Lake gold deposit upon which
Alexis Minerals Corporation has just released a positive feasibility study.
Thundermin also has various shareholdings in thirteen other junior resource
companies that are actively exploring for base metal, gold, chrome,
vanadium-titanium and diamond deposits in Canada.
Forward-Looking Statements
This news release may contain "Forward-Looking Statements" that involve risks
and uncertainties, such as statements of Thundermin's plans, objectives,
strategies, intentions and expectations. The words "potential," "anticipate,"
"forecast," "believe," "estimate," "expect," "may," "project," "plan," and
similar expressions are intended to be among the statements that identify
"Forward-Looking Statements". Although Thundermin believes that its expectations
reflected in these "Forward- Looking Statements" are reasonable, such statements
may involve unknown risks, uncertainties and other factors disclosed in our
regulatory filings that can be viewed on the SEDAR website at www.sedar.com. For
us, uncertainties arise from the behavior of financial and metals markets and
from numerous other matters of national, regional, and global scale, including
those of an environmental, climatic, natural, political, economic, business,
competitive, or regulatory nature. These uncertainties may cause our actual
future results to be materially different than those expressed in our
"Forward-Looking Statements". Although Thundermin believes the facts and
information contained in this news release to be as correct and current as
possible, Thundermin does not warrant or make any representation as to the
accuracy, validity or completeness of any facts or information contained herein
and these statements should not be relied upon as representing its views
subsequent to the date of this news release.
For further information on Thundermin Resources Inc. please visit Thundermin's
website at www.thundermin.com or the SEDAR website at www.sedar.com.
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