IP survey confirms large copper gold target at West Wyalong
30 September 2015
IP SURVEY CONFIRMS LARGE COPPER GOLD TARGET AT WEST WYALONG
HIGHLIGHTS:
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Ground IP survey confirms a large, broad area of increased chargeability
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The IP chargeability anomaly corresponds closely to the 1.4 km x 0.8 km magnetic low anomaly announced 17 July 2014
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The IP anomaly is also coincident with strong copper and gold geochemistry intersected by historical shallow aircore drilling - anomaly remains untested
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The results indicate a large copper gold target of porphyry/epithermal style mineralisation with potential similarities to nearby world class deposits, including Lake Cowal 37 km to the north
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The West Wyalong copper gold target is now defined - drill test plan to be designed
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Potential additional IP anomaly noted on south east portion of IP survey - follow up required
WEST WYALONG, NSW AUSTRALIA
Argent Minerals Limited (ASX: ARD, Argent, Argent Minerals or the Company) is pleased to announce the results of a high resolution ground induced polarisation (IP) survey conducted at the West Wyalong Project in NSW, Australia, a farmin joint venture between Argent Minerals and Golden Cross Operations Pty Ltd in which Argent Minerals has earned a 51% interest, and the right to earn 70% is currently active.
New South Wales
LACHLAN OROGEN
NORTHPARKES
The results of the IP survey confirm a large, broad area of anomalous increased chargeability that corresponds closely with the 1.4 km by 0.8 km magnetic low anomaly reported on 17 July 2014. The IP chargeability anomaly is also coincident with strong copper and gold geochemistry intersected by historical shallow aircore drilling.
COWAL
WEST WYALONG
CADIA
Australia
Argent Minerals Managing Director David Busch said, 'This development represents another major step forward for the West Wyalong Project. Following analysis performed by geophysicist Steve Collins of ARCTAN Services Pty Ltd, the large combined magnetic and IP feature is considered to be prospective for a porphyry/epithermal copper gold mineralisation system with potential similarities to significant deposits nearby, including the Lake Cowal mine.
'A key result of the IP survey is that the copper gold target positioning information is now of sufficient resolution for Argent to proceed with designing a drill test plan. The Company has decided to progress this as a priority'.
About the West Wyalong location
Located only 7 kilometres from the West Wyalong gold fields that produced 445,700 ounces of gold from 374,111 tonnes of material between 1894 and 1921, the West Wyalong Project is situated in the Macquarie Arc of the Lachlan Orogen, in a geological setting of Ordovician volcanics which hosts world-class porphyry copper-gold mines such as Newcrest's Cadia, China Molybdenum's Northparkes, and 37 kilometres to the north of West Wyalong - the Lake Cowal mine (Cowal).
Cowal was acquired by Evolution Mining Limited (Evolution) in July 2015 for $US550 million. Considered by Evolution to be 'one of Australia's most attractive gold assets', the December 2014 Cowal Mineral Resource has been estimated at 5.09 million ounces of gold, including an Ore Reserve estimate of 2.18 million ounces of gold.
Suite 6, Level 6, 50 Clarence Street, Sydney, NSW 2000
Phone +61 2 9262 2211 | Facsimile +61 2 9475 5346 www.argentminerals.com.au ABN 89 124 780 276
About the IP survey
The purpose of the West Wyalong survey was to obtain higher resolution IP data over the area of interest which Argent had previously identified as being potentially prospective for a porphyry copper gold deposit.
The Company had initially identified the potential anomaly in 2013 by reprocessing historical geophysics data that had been obtained from low resolution government magnetic and radiometric surveys.
In 2014 Argent carried out an airborne survey for higher resolution magnetic data, which significantly advanced interpretation of the subsurface geology and defined areas where the magnetic minerals in the host rock may have been altered by hydrothermal processes. The survey successfully identified an area of low magnetic rocks within a belt of predominantly magnetic high response, indicating thermal destruction of magnetism typically associated with volcanic intrusive processes. Several of the mineable porphyry deposits in eastern Australia have a very low IP response, particularly those with gold as a major component.
The August 2015 ground IP survey has confirmed a broad area of anomalism that is coincident with the results from the airborne magnetic survey. The survey has defined a weak but distinct zone of elevated IP chargeability response that corresponds closely to the observed magnetic low.
The results indicate broad, consistent subsurface geology such as a porphyry stock. Coincident potential for magnetite destruction and elevated IP chargeability indicate the possible presence of a sulphide mineralised porphyry stock at depths beyond the historical shallow aircore drill testing.
The combined magnetic and IP feature, together with the presence of high copper values in nearby drill results, is considered to be prospective for porphyry/epithermal style copper gold mineralisation with potential similarities to to significant deposits nearby, including that of the Lake Cowal mine.
The interpreted dimensions of the combined magnetic and IP anomaly are significant, being approximately 1.4 kilometres in the north-south direction, 800 metres from east to west, and extending to depth from approximately 200 metres.
Additional potential IP chargeability anomaly observed to the south east
The geophysicist has also noted another IP response in the south east corner of the surveyed area, which displays a similar positive chargeability response as the main target area. Argent Minerals is treating the IP results in the southern portion of the surveyed area with caution due to poor weather sustained during data collection in that section. Four receiver stations and respective results were removed from the survey due to erroneous results from excessive standing water (see line 6,239,600N in Figures 3 and 4), ARCTAN Services Pty Ltd filtered the erroneous results out prior to inversion modelling and a consistent gradient can be seen in the south west section of the surveyed area which indicates negligible effect from removal of the data points.
Given the proximity of this southeastern anomaly to the Narragudgil prospect located approximately 2 kilometres from the main prospect, and the potential for an expansion of the Narragudgil prospect footprint, follow up geophysical work is under consideration.
Next steps
The next steps will be to consider further IP survey work to the south east of the area recently surveyed, overlapping the current survey area and extending coverage toward the Narragudgil prospect.
In the event that the extended survey area confirms the additional potential IP chargeability anomaly to the south east, this will be considered for inclusion in the drill test plan to be designed for the main West Wyalong copper gold target.
THE EXPLORATION RESULTS IN DETAIL
About the magnetic anomaly and the closely correlating chargeability anomaly
Figure 2 shows the general location of the copper gold target in relation to the regional tectonics and mineral occurrences, including Lake Cowal mine to the north, the adjacent West Wyalong goldfields, and the Narragudgil and Yiddah North prospects within the West Wyalong Project tenement area.
37 km to Cowal mine
5.09 Moz gold Resource
WEST WYALONG
WYALONG
N
Exploration Licence Area
G I L M O R E
West Wyalong Goldfields 445,700 oz gold mined (1894 to 1921)
Airborne Magnetic Survey Area
YIDDAH FORMATION
N A R R A G U D G I L
Copper gold target
1.4 km x 0.8 km
V O L C A N I C S
Narragudgil prospect
S U T U R E
Total Magnetic Intensity
770 nT
-460 nT
kilometres
0 5
Yiddah North prospect
Figure 2 - West Wyalong regional tectonics, mineral occurrences, tenement position and prospect locations with background Total Magnetic Intensity image
Figure 3 shows the 3D magnetic susceptibility inversion model with associated cross sections (pseudosections) zoomed to the new target area. There is a clearly discernable magnetic low in the southern portion of the highlighted area of interest (darker blue colours) which appears to plunge to the south.
Figure 4 shows the 3D IP chargeability inversion model using acquired data from the August 2015 ground IP survey. The results show that the central portion of the area of interest is more chargeable than surrounding rock types, closely correlating with the magnetic low in Figure 3. The positive chargeability response in the southeast is encouraging also and will require further assessment in conjunction with further analysis of the Narragudgil Prospect.
3400 x 10-5SI
Cu Au Target
Narragudgil
3400 x 10-5SI
3400 x 10-5SI
Figure 3 - West Wyalong 3D Magnetic Susceptibility model - Horizontal slice at approximately 230m below the surface with West-East sections shown as Figures A and B
Cu Au Target
Potential additional anomaly
Narragudgil
Figure 4 - West Wyalong 3D IP chargeability model - Horizontal slice at approximately 230m below the surface with West- East sections shown as Figures A and B
Additional resistivity inversion modelling (not shown in this report) confirmed a broad resistive feature in the subsurface geology at depths below 200 m.
The response of this feature is consistent with that expected by a large porphyry stock.
About the coincident strong geochemistry
Shallow aircore drilling conducted by Newcrest Mining Limited (Newcrest) intersected strong gold and copper geochemistry, providing additional confirmation of the porphyry copper-gold signature. It is important to note that the drilling was performed by Newcrest in 2000, prior to the MIMDAS survey conducted during the 2002-2003 period.
A plan view and section from the 17 July 2014 announcement are reproduced in Figure 5 for ease of reference.
Intersections above the magnetic anomaly include gold from 0.05 g/t to 0.24 g/t, and copper to 645 ppm, which are considered to be strong geochemical anomalies in the context of shallow aircore drilling (see Appendix A for further details).
As can be seen from the cross section in Figure 5, the holes are considered as not having tested the magnetic anomaly. The same is true for the IP chargeability anomaly. Being performed as part of a broad grid-based geochemical mapping exercise which extended across a much larger region, the Newcrest shallow drilling did not target what we now know to be a strong magnetic anomaly with a coincident IP chargeability high. This is additionally confirmed by the absence of any such references in the company's historical exploration reports.
Had the exploration company known about the coincident magnetic and IP chargeability anomalies, there would have been a strong case for drilling much deeper holes.
CROSS SECTION A-B
Figure 5 - Magnetic low anomaly plan view at left showing position of selected Newcrest aircore drillholes, with section view at right confirming that the target area is not considered to have been tested
JORC Table 1
In accordance with section 5.8.2 of the ASX listing rules, Section 1 (Sampling Techniques and Data), and Section
2 (Reporting of Exploration Results) of Table 1 of the JORC Code are attached as Appendix B to this announcement.
For further information please contact:
David Busch Managing Director
Argent Minerals Limited
M: 0415 613 800
E: [email protected]
APPENDIX A - HISTORICAL DRILL HOLE INFORMATION
The information in Appendix A of the 17 July 2014 ASX announcement is reproduced here for convenience.
Table A is a compilation of historical aircore drilling results conducted by Newcrest in January 2000. Only holes related to magnetic anomaly are shown. Collar plan of these holes is shown in Figure 5 of this announcement.
Table A - West Wyalong historical aircore drilling assay results*
GDA
Easting (m)
GDA
Northing (m)
Zone
RL
(m) Azimuth Dip
EOH
(m)
Intercept (m)
From (m)
Au (g/t)
Cu ppm
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ACNG041
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526573
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6241184
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55
|
225
|
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No significant
|
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assays
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|
ACNG049
|
527013
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6240304
|
55
|
225
|
|
No significant assays
|
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ACNG050
|
526413
|
6240344
|
55
|
225
|
|
ACNG051
|
526673
|
6240344
|
55
|
225
|
|
ACNG056
|
526573
|
6239885
|
55
|
225
|
|
ACNG059
|
526653
|
6240784
|
55
|
225
|
|
ACNG060
|
526413
|
6240784
|
55
|
225
|
00 -900 89
00 -900 113.6
|
-900
|
79.3
|
6
|
32
|
0.06
|
n/a
|
|
-900
|
73.3
|
9.3
|
64
|
0.05
|
645
|
|
-900
|
74.4
|
4
|
60
|
0.22
|
|
-900
|
77.1
|
3.1
|
74
|
0.21
|
n/a
|
|
-900
|
85.6
|
2
|
80
|
0.24
|
n/a
|
00
00
00
00
00
-
Only intercepts for grades above background are shown.
APPENDIX B - JORC 2012 EDITION TABLE 1
WEST WYALONG GROUND IP SURVEY
The following information follows the requirements of JORC 2012 Table 1 Sections 1, 2 and as applicable for ASX release related to West Wyalong ground IP survey.
Section 1 - Sampling Techniques and Data
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Criteria
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Commentary
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Sampling techniques
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Argent Minerals is reporting a new ground IP survey conducted in August 2015 with processing and interpretation conducted by ARCTAN Services Pty Ltd (ARCTAN).
Ground IP Survey August 2015
Argent Minerals contracted Fender Geophysics Pty Ltd (Fender Geophysics) to carry out a ground IP Survey at Argent Minerals/Golden Cross Operations Pty Ltd exploration licence EL5915 at West Wyalong. A total of 6 square kilometres was surveyed. Equipment and sampling techniques employed in the survey are listed as follows:
Survey Type 3D Induced Polarisation
Array Offset pol dipole
Number of Arrays 6 arrays
Dipole Length 100m
Receiver Lines 1600m long of 16 dipoles of 100m length
Transmitter Line 3200m
Line Separation 200m
Domain Time Domain
Cycle 0.125Hz or 2 seconds
Fender provided a 5 man crew including 2 experienced field geophysicists, 1 experienced transmitter operator and 2 experienced field assistants. The survey consisted of six standard arrays of three lines each with two receiver lines of 17 electrodes each separated by 400m, a receiver dipole length of 100m, and a line of transmitter electrodes spaced at 100m giving a line separation of 3 x 200m. Each array covered an area of approximately 1600 metres by 600 metres, and the total surveyed area was approximately 6 square kilometres. The survey was conducted as an offset pole-dipole IP survey layout and was measured in the time domain to 2 seconds, or 0.125Hz. Results were provided to Steve Collins of ARCTAN and were inversion modelled using ResInv3DX64 inversion modelling software. ARCTAN provided results of chargeability, resistivity and magnetic susceptibility as a time slice and pseudosections.
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Drilling techniques
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Drilling was not conducted
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Drill sample recovery
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Drilling was not conducted
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Logging
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Drilling was not conducted
|
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Sub-sampling techniques and sample separation
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Drilling was not conducted
|
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Quality of assay data and laboratory tests
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Drilling was not conducted
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Verification of sampling and assaying
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All data was reviewed on a daily basis by Fender Geophysics prior to re-formatting and distribution to Argent Minerals personnel and consultant ARCTAN.
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Location of data points
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All data used in this report are in:
Datum: Geodetic Datum of Australia 94 (GDA94) Projection: Map Grid of Australia (MGA)
Zone: Zone 55
Two handheld Garmin GPS60 units were used to record point locations for receivers and transmitters giving an accuracy of ±5m.
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Data spacing and distribution
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Six arrays were employed with 100m receiver dipole length, 100m transmitter dipole length and a 200m line separation. Receiver lines totalled 1600m in length, the transmitter line totalled 3200m in length.
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Orientation of data in relation to geological structure
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Ground IP Survey lines were oriented east-west and the array was offset north-south. This direction was considered to best represent regional geological boundaries which occur along dominantly north-south trend.
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Sample security
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Chain of Custody was managed by Argent Minerals staff who oversaw data transfer from Fender Geophysics Pty. Ltd. to ARCTAN for processing.
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Audits or reviews
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A review of the survey logistics and interpretation of results has been undertaken by Argent Minerals staff
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Section 2 - Reporting of Exploration Results
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Criteria
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Commentary
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Mineral tenement and land tenure status
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Exploration by other parties
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The West Wyalong Project (currently exploration licences EL5195 and EL8001, NSW) is a joint venture between Golden Cross Operations Pty Ltd (49% interest) and Argent Minerals Limited (51% interest). Golden Cross Operations Pty Ltd is a wholly owned subsidiary of Golden Cross Resources Limited.
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In addition to the standard government royalties for the relevant minerals, a net smelter return (NSR) royalty of 2.5% is payable to Royal Gold, Inc.
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EL5195 and EL8001 are adjacent to the West Wyalong township and occupy western lease lands which have historically been employed mostly for crops growth and partly for pastoral usage. Heritage items have not been identified on the property.
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EL5195 is due to be renewed in January 2016 and EL8001 in October 2014.
45,000 ounces. Mining ceased in 1920 with a reported total production of 445,700 ounces from 340,000 tonnes (average grade 1.31 oz/t or 40 g/t Au). Post 1920, systematic exploration only commenced in 1981 when Mineral Management and Securities Ltd held EL 1658 over the Wyalong Goldfield and surrounding area (including part of EL 8001) until its relinquishment in January 1989.
-
Previous exploration work by different mineral exploration companies is summarised by historical tenements as follow:
-‐ EL 2179 Seltrust/Paragon Gold (1984-1986);
-‐ EL 2246 Lachlan Resources (1985 - 1988);
-‐ EL 3620 North Ltd/Gold Mines of Australia/Cyprus (1990-1998);
-‐ EL 4533 CRA (1993-1996);
-‐ EL 6515 Golden Cross Resources (1997-2000); and
-‐ EL 5915 Golden Cross Operations/Newcrest/MIM Exploration (2000-2006).
-
The extensive exploration activities performed by Golden Cross Operation on EL4615 over the period 1995 to 2000 included:
-‐ The entire licence area was flown with aeromagnetics and Quest EM;
-‐ 26 x RCP holes were drilled for 2,116.6 metres;
-‐ 234 x aircore holes were drilled for a total of 10,991 metres;
-‐ 7 x costeans were excavated for 272m;
-‐ 10 x mud/percussion holes were drilled for 807 metres;
-‐ The entire licence area was geologically mapped and interpreted at 1:25,000 scale;
-‐ 112 partial leach soils were collected;
-‐ 4309 samples of composited hand & auger soils were submitted for assay;
-‐ Re-assay of 32 air core pulps for Pt, Pd, Co, Ni and V;
-‐ A gravity survey was taken over the entire licence area; and
-‐ 778 rock chip samples were collected over all the various prospects.
-
During 2001 and 2002, exploration work carried out by Newcrest Operations under a joint venture agreement with Golden Cross Operation in the Narragudgil (south-eastern portion) area included:
-‐ 90 x Air Core drill holes for 7838.4 metres at the Narragudgil prospect ;
-‐ 10 x RCP holes for 1822.5 metres at Yiddah North prospect; and
-‐ 8 x combined Air Core/Diamond core holes for 1224 metres of air core, and 824.5 metres Diamond core.
-
Initial work carried out by MIMEX in 2002 included a compilation of historic drill results, review of existing core, mapping, reconnaissance ground magnetics, and MIMDAS surveys. A total of 57.5 line km of MIMDAS IP/MT were surveyed on 19 lines and five RC percussion holes for a total of 834m were drilled to test anomalous areas. The MIMDAS geophysical IP/resistivity, magnetotelluric system was used in the pole-dipole configuration with 100 dipoles. MIMEX withdrew its interest in the joint venture in June 2003.
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Reviews by Argent Minerals of past exploration including drilling, surface geochemistry and geophysical surveys highlighted two prospects: Narragudgil and Yiddah North Prospects, both directed towards porphyry style base metals (Cu-Au) in the Narragudgil Volcanics. These prospects are located in the south-eastern portion of the EL 5195 tenement area. A wide zone (400m) of principally propylitic alteration was identified during the drilling, extending in a north westerly
|
direction for around 3km through the licence area.
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Geology
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The Argent Minerals exploration strategy at West Wyalong primarily focuses on the targeting of porphyry style Cu-Au systems hosted in Ordovician arc rocks, as well as orogenic / structurally controlled quartz vein hosted gold deposits. The occurrences of major epithermal (Cowal), porphyry (Marsden, Yiddah North and Gidginbung) and intrusion related (Hobbs, Adelong) deposits provide encouragement that large intrusion/volcanic-related hydrothermal systems may exist in this part of the Lachlan Orogen. This, in addition to the discoveries at Cadia, near Orange, and Northparkes, near Parkes, shows that Ordovician age magmatic arc complexes in New South Wales are highly prospective for Cu-Au porphyries and associated epithermal deposits
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Drill hole Information
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The drillhole information derived from Newcrest archive files are:
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Drillhole collar ACNG041:
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Drillhole collar ACNG049:
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Drillhole collar ACNG050:
-
Drillhole collar ACNG051:
-
Drillhole collar ACNG056:
-
Drillhole collar ACNG059:
-‐ 526,573mE; 6,241,184mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 89 m.
-‐ 527,013mE; 6,240,304mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 113.6 m.
-‐ 526,413mE; 6,240,344mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 79.3 m.
-‐ 526,673mE; 6,240,344mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 73.3 m.
-‐ 526,573mE; 6,239,885mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 74.4 m.
-‐ 526,653mE; 6,240,784mN;
|
|
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 77.1 m.
-‐ 526,413mE; 6,240,784mN;
-‐ Elevation 225 mRL;
-‐ Dip -90 °; Azimuth 0°;
-‐ Final depth 85.6 m.
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Data aggregation methods
|
-
Interpretation of airborne magnetic and radiometric images with 10m x 10m cell size produced with by-cubic spline gridding method with bilinear interpolation.
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No weighting average techniques, or cut-off grades employed at this stage.
-
No metal equivalent values employed in this report.
|
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Relationship between mineralisation widths and intercept lengths
|
-
Mineralisation intersected in aircore holes is assumed to dip steeply westward at approximately 60°
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The true width is approximately 40% to 30% of down hole length.
-
Down hole lengths are reported.
- 70°. Drillholes are vertical.
|
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Diagrams
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An airborne Total Magnetic Intensity image with chargeability and drillhole plan has been included.
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Balanced reporting
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All anomalous intersections are included in this report.
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Other substantive exploration data
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All available exploration data relevant to this report has been provided.
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Further work
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Future work could involve a dipole-dipole IP survey to confirm and delineate the potential additional south east target, and then subsequent Diamond drilling to test the target(s).
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COMPETENT PERSON STATEMENTS
Exploration Results
The information in this report that relates to Exploration Results is based on information compiled by Mr. Clifton Todd McGilvray who is a member of the Australasian Institute of Mining and Metallurgy, an employee of Argent Minerals, and who has sufficient experience relevant to the style of mineralisation and type of deposit under consideration and to the activities being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting Exploration Results, Mineral Resources and Ore Reserves' (JORC Code). Mr. McGilvray consents to the inclusion in this report of the matters based on the information in the form and context in which it appears.