Projects
Tunkillia Project - South Australia
Helix Resources Limited 49%, Minotaur Exploration Limited earning 51% , excluding uranium rightsEL 3403, ELA2006/389 and EL 3335
Project Summary
- Resource inventory of 800,000oz Au and 1,600,000oz Ag;
- Minotaur completed $5M expenditure requirement to earn 51% and continuing to assess future development options;
- Exploration targets remain untested.
Project Background
Helix discovered the project in the mid 1990’s while exploring for gold under cover in the Gawler Craton of South Australia.The Tunkillia discovery, which was announced in late 1996, was one of the first gold discoveries in the Gawler Craton and the 20 square kilometre Tunkillia Prospect remains the largest robust gold-in-calcrete anomaly in the region. Subsequent exploration (1998-2002) was carried out in joint venture, initially with Acacia Resources Limited and later with AngloGold Limited following its takeover of Acacia.
In June 2003, Helix finalised the acquisition of AngloGold’s 49% interest in the Lake Everard Project, returning 100% ownership of the Project to Helix for the first time since 1998.
During 2003/2004 Helix completed a drill out of the Area 223 prospect, estimating a JORC resource of 720,000 ounces of gold.
By mid 2004, it became clear that the Tunkillia Project required a major injection of funds to give the project the critical mass required to enter into a feasibility study. The Helix Board decided at this time to seek a JV partner and in March 2005 Minotaur Exploration Ltd agreed to expend $5M to earn a 51% interest.
Since 2005 Minotaur has expended $5M carrying out additional drilling at Area 223 and several brownfields exploration campaigns using geophysics, geochemistry and drilling to test targets. In June 2007, Minotaur released a revised combined measured, indicated and inferred estimate inventory of 800,000oz Au and 1,600,000oz Ag within the Area 223 deposit.
Geology
The Gawler Craton is broadly divided into three main geological units, Archaean crystalline basement, highly deformed Palaeoproterozoic metasediments and granites, and less deformed Mesoproterozoic volcanics, clastic sediments and granite. Almost all gold and copper mineralisation found in the Gawler Craton is directly associated with Mesoproterozoic magmatism.The host rocks to the Tunkillia prospect are medium- to coarse-grained granitoids of the Tunkillia Suite, that have been intensely sheared and brecciated within the Yarlbrinda Shear Zone.
In a regional context, the Tunkillia area shows evidence of extensive alteration. Large zones of demagnetisation (alteration of primary magnetite to ilmenite) are observed in aeromagnetic images, from which Helix defined a western and eastern demagnetised zone within the northern Yarlbrinda Shear Zone. Area 223 is located within the western demagnetised zone along which large volumes of fluid were focused, particularly along the margins of the shear zone producing the gold deposit and alteration.
At the prospect scale, gold mineralisation at Tunkillia is associated with zones of intense sericite alteration, and quartz and sulphide veining.
Resources
| Oxide: | 5.7Mt @ 1.3g/t for 230,000 oz Gold (0.5g/t cutoff) |
| Measured: 1.2Mt @ 1.8 g/t Au – 66,000oz | |
| Indicated: 2.0Mt @ 1.3g/t Au – 86,000oz | |
| Inferred: 2.5Mt @ 1.0g/t Au – 77,000oz | |
| Primary | 8.6Mt @ 2.1g/t for 570,000 oz Gold (1.0g/t cutoff) |
| Indicated: 4.2Mt @ 2.0 g/t Au – 270,000oz | |
| Inferred: 4.4Mt @ 2.1 g/t Au – 300,000oz | |
| 8.6Mt @ 5.7g/t for 1,600,000 oz Silver (estimated for blocks with >1g/t Au) | |
| Indicated: 4.2Mt @ 5.7g/t Ag – 770,000oz | |
| Inferred: 4.4Mt @ 5.7g/t Ag – 810,000oz |
The current resource consists of a mineralisation inventory of 800,000oz gold and 1,600,000oz silver to a depth of 200m below surface. Full details of the methodology were released by Minotaur in June 2007.
The resource estimation was made after additional drilling by Minotaur during 2006/2007 highlighted an extended area of gold mineralisation within the oxide zone and increased the level of confidence in the coherence of the oxide zone capping to the Tunkillia mineralisation.
Higher grade intersections are generally spatially associated with a highly weathered mafic dyke which strikes approximately grid N-S through Area 223.
