The Thackaringa project is located within the Broken Hill Block of the Curnamona Province and is composed of Willyama Supergroup high grade regional metamorphic gneisses, schists and amphibolites. Within the project area the local geology is dominated by quartz-albite-biotite gneiss, quartz-albite gneiss, and amphibolite dykes. The extensive stratabound cobalt-pyrite mineralisation at each prospect (Pyrite Hill, Big Hill and Railway) is hosted by quartz-albite gneiss.
The updated Total Mineral Resource estimate at the Thackaringa Project includes:
Additional resource potential has been defined through the identification of the following exploration targets:
Note: Small rounding errors may have occurred in the compilation of mineral resources.
The potential quantity and grade of these targets is conceptual in nature. There has been insufficient exploration to define a Mineral Resource and it is uncertain if further exploration will result in determination of a Mineral Resource.
Mineralisation at the three prospects has a combined strike length of 4.5 kilometres with widths varying from 25 metres to 100 metres. The increased thickness is typically due to the extensive development of tight isoclinal folding within the pyritic horizon. The 2016 drilling program comprised eight fully-cored diamond drill holes at three locations – Pyrite Hill, Big Hill and Railway (Figure 1).
The work was undertaken primarily to provide sufficient material to undertake meaningful metallurgical test work. By twinning previous RC holes the JV was able to confirm the tenor of mineralisation and compare the assays and sampling protocols for historical RC percussion drilling vs diamond drilling.
Two holes were drilled at each of Pyrite Hill and Big Hill prospects and four holes drilled along the much longer mineralised strike length at Railway Prospect, for a total of 1,484.8m. All 2016 holes were drilled at declinations between 50 and 60 degrees into the steeply-dipping host lithology.
A total Inferred Mineral Resource of 33.1Mt at 833ppm cobalt (at a 500ppm Co cut-off) has previously been estimated at the Thackaringa Resource.
The current 2017 drilling program comprises approximately 5,500m of RC drilling plus a 1,500m of diamond drilling. The program is designed to extend the drilling coverage and improve drilling density in support of future Mineral Resource estimations, replace some of the historical drilling for QA/QC purposes and provide material for further metallurgical testwork.
Railway Trend Results
At Railway, current assays conﬁrm high-grade intersections of mineralisation within a wide and continuous envelope. Best mineralised intercepts include:
- 16DM06 – 42m @ 1,615ppm Co from 28m;
- 16DM07 – 25m @ 1,232 ppm Co from 35m and 26m @ 1,456 ppm Co from 71m;
- 17THD06 – 46m @ 1,136ppm Co, 11.4% S and 10.1% Fe from 39m;
- 17THR008 – 41m @ 1,319ppm Co, 12.2% S and 11.2% Fe from 37m; and
- 17THR011 – 53m @ 1,116ppm Co, 12.0% S and 10.9% Fe from 30m.
Pyrite Hill Results
At Pyrite Hill, assays confirm the mineralisation within the host lithology. Best mineralised intercepts include:
- 16DM02 – 23m @ 1,392ppm Co from 127m;
- 17THR017 – 58m @ 1,383ppm Co, 13.2% S and 12.8% Fe from 54m;
- 17THR021 – 20m @ 1,204ppm Co, 13.1% S and 12.7% Fe from 44m;
- 17THR024 – 14m @ 1,436ppm Co, 12.3% Fe & 12.1% S from 68m; and
- 17THR024 – 43m @ 1,082ppm Co, 9.2% Fe & 9% S from 96m Including – 29m @ 1,363ppm Co, 10.5% Fe & 10.5% S from 110m;
2016 Big Hill Results
The Big Hill deposit is an off-set southwestern extension of the high-grade metamorphic host at Railway. Two holes were drilled towards the south-western end to confirm the depth and strike extensions of known cobalt-pyrite mineralisation. The mineralisation appears to thin and become lower grade at the southern end of the Big Hill-Railway trend. Big Hill may be more distant to mineralising fluid pathways along faults or dilational structures, but this has yet to be determined. There remains a 1km strike length of undrilled and lightly drilled host lithology between Big Hill and Railway, much of which is close to interpreted faulting and needs to be investigated.
The company confirms that it is not aware of any new information or data that materially affects the information included in the relevant market announcements and that all material assumptions and technical parameters underpinning these mineral resource estimates in the relevant market announcement continue to apply and have not materially changed.
COMPETENT PERSONS STATEMENT
The information in this report that relates to exploration results, Mineral Resources and Targets is based on information compiled by Mr Anthony Johnston, BSc (Hons), who is a Member of the Australian Institute of Mining and Metallurgy and who is a non-executive director of Cobalt Blue Holdings Limited, the Chief Executive Officer of Broken Hill Prospecting Limited and the Technical Manager of the Joint Venture. Mr Johnston has sufficient experience which is relevant to the style of mineralisation and type of deposits under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 & 2012 Edition of the “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Mr Johnston consents to the inclusion in the announcement of the matters based on his information in the form and context that the information appears.