Wilcherry Project, South Australia (Alliance 71.09%)
The Project is located within the southern part of the Gawler Craton in the northern Eyre Peninsula and comprises seven exploration licences covering 1,400 km2 and is prospective for gold and base metals.
The Wilcherry Project is a joint venture between Alliance Craton Explorer Pty Ltd (71.09%) and Trafford Resources Pty Ltd (28.91%).
Alliance is sole funding $3.2 million exploration in FY2018, and subject to expenditure, may move to approximately 77% ownership.
The exploration objectives of the joint venture are twofold:
- to assess the potential of the high grade Weednanna Gold Prospect for economic development, and
- to assess the regional potential for base metals.
Figure 1. Wilcherry Project: Location of prospects and HEM / MLEM targets on gravity image
Weednanna Gold Prospect
Weednanna is the most advanced gold prospect at the Wilcherry Project, is located 45 km north of the township of Kimba.
Historic exploration targeted primary gold beneath coincident calcrete soil anomalies and magnetic highs. This work identified a calc-silicate and magnetite (iron) skarn system containing discrete intersections of high grade gold.
In 2017-18, Alliance completed 92 RC drill holes for 14,345m to test the strike, dip and plunge continuity of four historic high-grade intersections referred to as Targets 1, 2, 3 and 4, plus initial drilling at Target 5. Refer Figure 2.
Fifty-eight (58) holes reported intercepts >1g/t Au, 17 of which returned grade x thickness >50g/t*m, as follows(1):
- 17WDRC003 (T1): 49m @ 6.3 g/t Au from 45m (incl. 21m @ 10.66 g/t Au from 48m)
- 17WDRC011 (T2): 10m @ 6.79 g/t Au from 79m (incl. 3m @ 15.55 g/t Au from 81m)
- 17WDRC012 (T2): 2m @ 61.09 g/t Au from 167m
- 17WDRC013 (T2): 7m @ 11.05 g/t Au from 82m (incl. 4m @ 17.58 g/t Au from 84m)
- 17WDRC017 (T3): 14m @ 36.1 g/t Au from 118m (incl. 5m @ 95.6 g/t Au from 120m and 7m @ 7.37 g/t Au from 147m)
- 17WDRC029 (T1): 30m @ 2.95 g/t Au from 53m
- 17WDRC030 (T1): 16m @ 7.66 g/t Au from 81m (incl. 8m @ 12.90 g/t Au from 88m)
- 17WDRC031 (T1): 41m @ 1.62 g/t Au from 44m
- 17WDRC032 (T1): 60m @ 5.65 g/t Au from 47m (incl. 9m @ 15.57 g/t Au from 63m and 8m @ 13.38 g/t Au from 99m)
- 17WDRC046 (T3): 7m @ 12.15 g/t Au from 153m (incl. 4m @ 18.81 g/t Au from 154m)
- 17WDRC051 (T1): 35m @ 3.65 g/t Au from 43m (incl. 9m @ 8.91 g/t Au from 44m)
- 17WDRC057 (T2): 6m @ 13.63 g/t Au from 59m (incl. 3m @ 26.6 g/t Au from 62m
- 17WDRC067 (T4): 15m @ 18.21 g/t Au from 107m (incl. 7m @ 35.94 g/t Au from 109m)
- 17WDRC070 (T4): 3m @ 25.45 g/t Au from 81m (incl. 1m @ 74.2 g/t Au from 81m)
- 18WDRC003 (T4): 16m @ 3.2 g/t Au from 84m
- 18WDRC005 (T4): 12m @ 10.2 g/t Au from 92m (incl. 4m @ 28.1 g/t Au from 96m)
- 18WDRC006 (T4): 4m @ 12.4 g/t Au from 52m
These drilling programs have demonstrated that the high-grade gold lodes are ovoid to rod-like in geometry and have continuity along strike. Close-spaced drilling is required for accurate definition.
(1) Refer to Alliance’s ASX announcements dated 3 April 2017, 10 April 2017, 28 August 2017, 30 November 2017, 10 January 2018 and 23 April 2018.
Figure 2. Weednanna drill hole collars and significant gold intercepts
A high resolution gravity survey was completed at Weednanna in April 2018. When combined with the existing geophysical datasets, the gravity data will provide a powerful targeting tool to help unlock the potential of the Weednanna gold system.
This improved understanding of the distribution of gold at Weednanna will be used to construct a 3D geological model of the prospect and planning further exploration with a view to establishing a mineral resource estimate in H1 2018.
Metallurgical testwork from Targets 1, 2, 3 and 4 indicates that gold mineralisation is amenable to conventional grinding and cyanide recovery techniques.
Planned work includes establishing a maiden mineral resource estimate in 1H 2018, together with a staged program of metallurgical work with the aim of optimising gold recovery and culminating in process design criteria and capital and operating costs for the processing base case.
The outcomes of both work streams, if positive, will feed into a scoping study in 2H 2018.
Regional Targets for Base Metals
In early 2017, a regional high-resolution helicopter borne electromagnetic (HEM) survey was flown to test for conductors associated with massive sulphide base metal deposits. The HEM survey identified 26 late time conductors.
During early 2018, ground moving loop electromagnetic (MLEM) surveys were completed over the remaining HEM target areas to better define those targets for drilling.
Three diamond holes and six RC holes were completed at six HEM/ MLEM targets for base metals in 2017, as follows:
Two diamond drill holes completed at Zealous targeting tin associated with massive sulphides;
One diamond hole was completed at Telephone Dam Prospect targeting zinc-lead-silver;
Six RC holes completed to test four regional MLEM targets for base metals, with best results as follows:
- 3m @ 0.4% Zn from 159m to EOH in 17EMRC006 at HEM / MLEM T2 (North), and
- 39m @ 8% total graphitic carbon from 116m in 17EMRC001 at HEM / MLEM T5.
In early 2018, eight MLEM targets were RC drilled for 1,256 m. Results are awaited.
Six MLEM targets will be drilled using a multipurpose rig capable of rotary mud precollars and triple tube diamond core tails for 1,960 m. Drilling commenced in April 2018.
Background and Previous Exploration
The Project area is predominantly overlain by a shallow veneer of transported cover that has prevented exploration by early prospectors. Drilling by modern explorers has identified significant mineralised systems hosted within Palaeoproterozoic calcareous and iron-rich metasediments which are intruded by Hiltaba Suite Granites that are responsible for widespread gold, uranium and base metal mineralisation in the Gawler Craton. The discovery of high grade tin in 2012, which had previously not been recognised in the district, suggests a more complex mineralised history than previously thought.
The Project area has been explored since the 1970’s by companies including Pan Continental Mining, Asarco and Marumba Minerals for uranium and Broken Hill Type base metals associated with the Paleoproterozoic Hutchison Group metasediments. This resulted in the discovery of the Menninnie Dam lead-zinc-silver deposit (not part of the Project) and the Telephone Dam lead-zinc-silver occurrence.
During the 1980’s, the Shell Company of Australia and WMC continued to explore the area for lead and zinc. Shell (later Acacia) in joint venture with Aberfoyle then refocussed exploration onto copper and gold utilising calcrete sampling to identify and prioritise target areas for drill testing.
In 1997 Acacia, identified a strong gold-in-calcrete anomaly at the Weednanna prospect which is coincident with a prominent NNW-trending magnetic anomaly. Successive drilling campaigns identified gold mineralisation associated with skarn alteration and brecciation in the contact aureole of the adjacent granite. Weednanna is now known to be a magnetite breccia in carbonate altered rocks forming a skarn near the contact with a granite intrusion and containing elevated gold, bismuth, tin, uranium, lead and zinc.
In 2002, Aquila Resources acquired the Project tenements to explore for IOCG deposits similar to Olympic Dam. In 2006, Trafford Resources Ltd (Trafford) acquired the Project tenements from Aquila.
Trafford and IronClad Mining Limited (IronClad) made a substantial investment on the Project, including but not limited to, defining Direct Shipping [iron] Ore (DSO) in magnetite skarns, banded iron formations and near surface iron oxide deposits. Trafford established Mineral Resources totalling 224 Mt @ 28.8% iron in seven deposits, with 2.9 Mt @ 55.5% iron being either DSO or Dry Magnetic Separation product (source: Trafford Annual Report 2014).
In 2012-13, drilling programs by IronClad to test an outcrop of high grade hematite at the Zealous prospect, 13km NE of Wilcherry Hill, intersected high grade tin (cassiterite) hosted by a magnetite skarn which has been weathered to goethite and limonite. The best intercepts from these programs returned 7m @ 3.28 % Sn from 52m in 12ZLRC007 and 5m @ 2.29 % Sn from 128m in 13ZLRC001(2). The host rocks are Palaeoproterozoic sediments adjacent to a granite footwall.
The discovery of high grade tin in this region potentially represents a new and significant tin province in South Australia.
(2) Refer to Tyranna Resources Ltd's ASX Announcement dated 2 August 2016 for further details.