De Grey Mining Ltd
ASX Announcement
17 August 2016
De Grey confirms High Grade Footwall Lode Extension at Wingina
ASX Code DEG
ABN 65 094 206 292
COMPANY DIRECTORS
Simon Lill
Executive Chairman
Davide Bosio
Non-executive Director
Steve Morris
Non-executive Director
Craig Nelmes
Company Secretary/CFO
CONTACT DETAILS
Principal & Registered Office Level 2, Suite 9
389 Oxford Street
Mt Hawthorn WA 6016
PO Box 281
Mt Hawthorn WA 6016 www.degreymining.com.au [email protected]
T +61 8 9381 4108
F +61 8 9381 6761
Highlights
De Grey Mining Ltd (ASX: DEG, "De Grey", "Company") is pleased to provide an update on the Wingina "Deeps" Diamond drilling program.
Highlights
-
Wingina Footwall Lode extended into fresh bedrock
-
High grade gold mineralisation now defined to ~350m below surface and remains open
-
First hole of the Wingina "Deeps" programme, WRC211D intersects:
4m @ 5.57g/t Au from 416m including:
1m @ 5.64g/t Au from 417m and;
1m @ 13.80g/t Au from 419m
-
Screen fire check assay results show high level of repeatability:
-
94.7% recovery based on 24-hour cyanide bottle roll BLEG extraction on this fresh bedrock mineralisation similar to oxide zone.
-
Second "Deeps" hole WRC211D2 completed, with samples in transit to laboratory. The hole intersected similar sulphide altered and veined BIF and Chert sequence.
-
Third "Deeps" hole recently commenced aiming to intersect the Footwall Lode ~60m further to the east.
De Grey Executive Chairman, Mr. Simon Lill, commented
"We are delighted with the high grade result as it confirms the high grade Footwall Lode extends into the fresh bedrock. The excellent high gold recovery from the preliminary BLEG results augurs well for potential underground mining and processing evaluation studies".
Turner River - Unlocking Shareholder Value
Wingina Gold Deposit
The Wingina Gold Deposit is located in an infrastructure rich area, 50km south of Port Hedland in the Pilbara region of Western Australia, with excellent access via dominantly bitumen roads.
The deposit is well drilled with high grade gold mineralisation hosted in a sequence of Banded Iron Formation (BIF) and Chert. Continuous high grade gold mineralisation (>1.5g/t) is hosted within two sub-vertical lodes termed the Hanging Wall and Footwall Lodes which extend over a 600m strike length and are currently drill tested to 200 - 250metres below surface.
A Total Mineral Resource Estimate of 268,000 ounces of gold, including 156,000 ounces in the Measured category and 48,000 ounces in the Indicated category, has be defined at Wingina. The remaining Inferred category relates to generally deeper portions of the deposit which have received less drilling density to date. The deposit is deeply weathered resulting in peripheral zones of lower grade (0.5-1.5g/t) remobilised "supergene" gold mineralisation located adjacent to the higher grade lodes.
De Grey considers the Wingina deposit will most likely be developed as an open pit and underground mining operation with additional ore sourced from satellite open pits within economic trucking distance. A simple CIL processing plant, typical of many gold mines in Western Australia, is the preferred processing option due to the excellent recoveries (>90%) achieved in previous metallurgical testwork on the oxide ore. The Mount Berghaus (43,000oz) and the Amanda (35,000oz) gold deposits, both located within 10km of Wingina, are expected to provide additional ore feed.
The Company is currently assessing the most advanced prospects within the Turner River Project that are considered likely to provide further additional open pittable gold resources and support the proposed Wingina development.
Accordingly, recent drilling has been undertaken at the Discovery VMS Au-Ag-Cu-Pb Zn deposit to better define shallow open pittable mineralisation. Encouraging preliminary results from 4m composite samples have recently been reported (ASX release dated 27 July 2016). The final 1m re-samples are expected to be finalised and reported during August.
Wingina "Deeps" Drilling Results
The current Wingina "Deeps" drilling program aims to extend the high grade Footwall "Central" Lode into the fresh bedrock. Two drill holes (WRC211D and WRC211D2) have now been completed with a third hole currently underway.
Drill holes WRC211D and WRC211D2 have both intersected a broad sequence of fresh altered BIF and internally folded Chert sequence with minor brecciation. Variable sulphide, alteration and vein development is noted throughout a large portion of the sequence.
In WRC211D, broad zones of anomalous (>0.1g/t) gold mineralisation are evident throughout the altered sequence with the most significant intercepts 11m @ 1.03g/t Au and 4m @ 5.57g/t Au including 1m @ 13.8g/t Au. This high grade mineralisation is interpreted to represent the down plunge extension of the high grade Footwall Lode (Fig 1).
Screen fire assays have also been completed on the individual higher grade samples and results indicate high repeatability between the two methods.
Table 1 Comparison of Fire Assay to Screen Fire Assay, WRC 211D
|
Hole ID
|
From
|
To
|
Fire Assay Original (Au g/t)
|
Screen Fire
(Au g/t)
|
|
WRC211D
|
416
|
417
|
2.16
|
2.21
|
|
WRC211D
|
417
|
418
|
5.64
|
5.89
|
|
WRC211D
|
418
|
419
|
0.68
|
0.8
|
|
WRC211D
|
419
|
420
|
13.8
|
12.55
|
|
|
|
WRC211D
|
425
|
426
|
1.85
|
1.5
|
|
WRC211D
|
426
|
427
|
3.29
|
3.29
|
Additional BLEG (Bulk Leach Extractable Gold) assays were also undertaken of the same individual high grade samples as preliminary check of the potential recoveries of the fresh bedrock ore. Recovery results are positive with an average extraction of 94.7%% in the BLEG samples.
As a cautionary note, the BLEG analytical method involves taking a 1kg sub-sample of the mineralisation, adding a cyanide solution to saturation, then bottle rolling the cyanide saturated sample for 24 hours. Once complete, a sample of the aliquot is assayed as a test of the gold extracted from the material. The method is a preliminary test of recovery via cyanide solution similar to how material may be treated in a cyanide leach plant. Further detailed testwork will be required to fully test the recoveries of fresh bedrock mineralisation.
Table 2 BLEG extraction results
|
Hole ID
|
From
|
To
|
BLEG
Aliquot Assay
|
BLEG Tail Fire Assay
|
BLEG Total Au
|
% Extraction Total BLEG Au
|
|
WRC211D
|
416
|
417
|
1.93
|
0.15
|
2.08
|
92.8%
|
|
WRC211D
|
417
|
418
|
5.27
|
0.32
|
5.59
|
94.3%
|
|
WRC211D
|
418
|
419
|
0.69
|
0.04
|
0.73
|
94.5%
|
|
WRC211D
|
419
|
420
|
10.5
|
0.52
|
11.02
|
95.3%
|
|
WRC211D
|
425
|
426
|
1.32
|
0.05
|
1.37
|
96.4%
|
|
WRC211D
|
426
|
427
|
3.12
|
0.16
|
3.28
|
95.1%
|
|
Average 94.7%
|
Fig 1 Wingina Longsection, showing location of WRC211D intersection
Table 3 Drill hole location data
|
Hole ID
|
Easting (m)
|
Northing (m)
|
RL(m)
|
Azimuth(°)
|
Dip(°)
|
Depth(m)
|
|
WRC211D
|
664847
|
7694550
|
84.30
|
142
|
‐64
|
516.80
|
GDA94, Zone 50
Table 4 Drill results
|
Hole ID
|
From (m)
|
To (m)
|
Interval (m)
|
Grade (g/t)
|
Gram metres (g*m)
|
|
WRC211D
|
383
|
394
|
11
|
1.03
|
11.3
|
|
397
|
398
|
1
|
0.73
|
0.7
|
|
408
|
409
|
1
|
0.55
|
0.6
|
|
416
|
420
|
4
|
5.57
|
22.3
|
|
including
|
417
|
420
|
3
|
6.71
|
|
including
|
419
|
420
|
1
|
13.8
|
|
425
|
427
|
2
|
2.57
|
5.1
|
|
including
|
426
|
427
|
1
|
3.29
|
|
431
|
434
|
3
|
0.63
|
1.9
|
Overall intercept using lower cutoff 0.5g/t and 2m internal dilution
Higher grade including intercept using lower cutoff 3g/t and 2m internal dilution