The West Wyalong Tenements are located one kilometre to the east of the West Wyalong township and approximately 470 kilometres west of Sydney . EL 5915 contains part of the historic West Wyalong goldfield.
The rocks underlying EL 5915 form part of the Palaeozoic Lachlan Geosyncline which is divided into a number of structural zones. EL 5915 is situated over the boundary of two of these, the Wagga-Omeo Zone to the west and the Parkes zone to the east. This boundary is defined by a major sub-structure, the Gilmore Suture, a mobile crustal zone of prolonged and intense deformation coupled with igneous activity. A number of significant mineral deposits and many small deposits are distributed along this structure.
A review of geophysical data within the West Wyalong Tenement has indicated a subtle circular gravity low (<21 milligal) corresponding to localised magnetic highs which was interpreted to be a vent or late stage intrusive phase of the dense intrusion. The main zones of anomalous geochemistry in the area form an annulus around this apparent late stage intrusive feature. It is thus considered to define an area where future exploration should be concentrated. Various zones of apparent alteration, faulting and localised intrusions have been identified elsewhere in the area. Many of these appear to have been ignored or under-explored. Several of these features have encouraging correlations with geochemistry.
In November 2007 Argent undertook an initial phase of drilling comprising three vertical percussion holes of a proposed six-hole programme. The holes were drilled to depths of up to 120m for a total 336m. The purpose of this drilling was to begin the evaluation of the potential for disseminated copper gold mineralisation in the vicinity of the dense non-magmatic igneous body identified from the review of the geophysical data.
Holes APG1 and APG2 intersected diorite with chlorite alteration, epidote and up to 1% pyrite. No significant gold mineralisation was identified from analysis of the chips. Hole APG3 intersected chlorite schist with carbonate veining and minor quartz. Analyses of the chips generally returned low gold values except for the 2m interval between 106-108m, which returned a grade of 19.1 g/t. This is a significant result as gold mineralisation had not been reported from this area previously.
A wide paleochannel draining the West Wyalong gold field to the north was drilled with three aircore holes to assess the possibility of there being gold in any gravels or a significant accumulation of iron rich pisolites .The best gold grade encountered was 0.13g/t over 2m .The pisolites were contained within a two to five metres thick sequence.
Five shallow close spaced aircore holes were drilled at Mallee Vale to follow up previous drill hole AMV002 intersection of 6.1g/t Au over 4m. These holes were drilled at 10m centres surrounding the original intersection in order to determine the trend of the mineralisation. The results indicate that the extent of the mineralisation is very limited and no further work is planned for this prospect.
Two 152m angle holes were drilled approx 3kms from AGC001 to follow up an intersection of 2m @ 19.2g/t Au in a previous vertical hole (Hole AWPG003 ) at a depth of 106m. The holes failed to intersect any extensions of that mineralisation.
A relatively deep (196m) hole (AGC001) was drilled to test a large coincident 21 milligal gravity anomaly and 850 nanoteslas magnetic anomaly. The anomaly, which lies on the Gilmore suture, is very large; over 5 kms wide and contains several gold and copper soil anomalies as shown in the diagram below. The Gilmore Suture to the south contains several porphyry copper gold systems including Yiddah, Mandamah, Monza, Cullingerai, Estori, and The Dam and Marsden and Cowal to the north.
Hole AGC001was drilled to determine if there was any sign of increasing alteration with depth to indicate the presence of mineralising hydrothermal solutions which could form a porphyry copper-gold system.
The hole returned encouraging results including two strongly altered zones at 60m and 190m. The zone from 60 to 76 metres contained arsenopyrite and traces of chalcopyrite, galena and pyrite with 2m assaying 22.6g/t gold including 1m of 43.1g/t gold. The zone from 190 to 196(EOH) encountered strong alteration that could be related to hydothermal solutions.
This hole will be deepened in the near future to determine the extent and intensity of the alteration and to look for indications of porphyry style copper-gold mineralisation.
In addition, a further 600m of inclined percussion drilling was carried out to evaluate reef extensions at depth below abandoned workings at the Callback, Mallee Vale, Stanley Blow, Pine Ridge and Pine Hill mines and encouraging results were obtained from two holes. Mallee Vale hole AMV2 intersected four metres from a depth of 28m which returned a grade of 6.11g/t gold and Pine Ridge hole APR2 intersected two metres from a depth of 36m which returned a grade of 1.48 g/t gold.