Havilah controls more than 16,000 km² of mineral tenements in the Curnamona Craton in northeastern South Australia. This highly mineralised region is host to the largest lead-zinc deposit in the world at Broken Hill. Havilah’s cost-effective exploration over the last two decades has been very successful in delineating a JORC Mineral Resource metal inventory of 1.3 million tonnes of copper, 3.2 million ounces of gold, 43,400 tonnes of cobalt and 451 million tonnes of iron ore, plus appreciable molybdenum, sulphur, tin, uranium and the potential for rare earth elements.
The Curnamona Copper Belt is a world-class copper-gold-cobalt province, with widespread sulphide mineralisation typically occurring in a 100-150 metre thick carbonate-rich horizon at a major redox boundary. The geological setting is similar to the Zambian Copper Belt, with the following strong geological analogies:
Regionally extensive copper mineralised 'prospective horizon' at a major redox boundary;
Metasediments folded into a series of granite-cored domes;
Ore grades where structural disruption and preparation ('broken rocks'); and
Persistent cobalt association, but gold is an added bonus in South Australia.
Aeromagnetics clearly identifies the redox boundary and the position of the prospective mineralised horizon. The picture above shows the prospective horizon extending for over 200 km around several major structural domes.
Over $80 million (in current dollars) spent by major company tenement holders in the past has led to the discovery of numerous promising prospects, many with ore-grade intersections that have never been adequately followed up (see map above). Extensive younger sediment cover has masked the mineralisation, but geophysics, detailed knowledge of the regional geology and in-house drilling capability has turned this into an advantage for Havilah, resulting in the discovery of several sizeable mineral deposits (eg Kalkaroo and North Portia). In all cases, the probability for discovery of repetitions of Kalkaroo style copper-gold-cobalt-molybdenum mineralisation is high both in the Kalkaroo north and south domes and in other domes (eg Lake Charles, Eurinilla, Benagerie domes). Other known styles of copper-gold mineralisation include skarn hosted (eg Croziers) and IOCG type (eg Lake Charles).
In addition, widespread lead-zinc mineralisation is found in a particular horizon just above the redox boundary that is recognised throughout the region as the Broken Hill lode equivalent (eg at Deep Well, Jessica and McBrides Dam prospects).
South of the main highway is the Mutooroo Cobalt District where copper-cobalt sulphide mineralisation occurs in well defined shear and lode structures in high grade metamorphic rocks similar to those hosting the giant Broken Hill deposit (eg Mutooroo). Within this district there are numerous prospects, some with ore-grade copper intersections dating from the 1960’s that have never been assayed for cobalt or gold, that is known to be associated with the mineralisation. Recent surface geochemical sampling has highlighted widespread, exceptionally high copper and cobalt values, confirming a major new copper-cobalt sulphide mineralised district.
Also south of the transcontinental railway are large iron ore deposits at Maldorky, Grants and Grants Basin. All projects are in close proximity in relation to heavy duty rail links to the Spencer Gulf ports of Whyalla, Port Augusta and Port Pirie (and also Port Waratah and Port Kembla to the east).
The Group will drive exploration value through the detailed evaluation of its tenements to identify quality exploration prospects and targets. The Board of Directors believes that it is strategically important for the Company’s longer-term sustainability to maintain a focus on ensuring a future pipeline of prospective opportunities.
This strategy will entail maintaining a balanced portfolio in terms of risk and reward, containing both higher-value, near-term exploration prospects while ensuring a holding of prospective acreage capable of sustaining longer-term production and mineral resource growth.
Accordingly, a focused and methodical exploration strategy will be implemented, concentrating on high prospectivity geological targets. Methodologies will continue to assess exploration and mineral resource replacement potential in value terms. The objective is that the allocation of exploration expenditure is commensurate with the potential value of exploration targets.
Supported by funds raised from the recent capital raisings, the Group plans to undertake exploration drilling of several high conviction copper-gold exploration targets within its large prospective mineral tenement holding during the course of the calendar year. This will be carried out by Havilah’s own drilling crew using a dry-hired percussion drilling rig, that has proven itself to be effective in past drilling campaigns in the Curnamona Craton.
Footnotes to 5 June 2020 JORC Ore Reserve and Mineral Resource Tables
Numbers in tables are rounded
¹ Details released to ASX: 18 June 2018 (Kalkaroo)
² Details released to ASX: 18 October 2010 and 5 June 2020 (Mutooroo)
³ Details released to ASX 30 January 2018 & 7 March 2018 (Kalkaroo)
⁴ Note that the Kalkaroo cobalt Inferred resource is not added to the total tonnage
⁵ Details released to ASX: 10 June 2011 applying an 18% Fe cut-off (Maldorky)
⁶ Details released to ASX: 5 December 2012 applying an 18% Fe cut-off (Grants)
⁷ Details released to ASX: 4 June 2009 using a grade-thickness cutoff of 0.015 metre % eU3O8 (Oban)
Summary of governance arrangements and internal controls in place for the reporting of Ore Reserves and Mineral Resources
Ore Reserves and Mineral Resources are estimated by suitably qualified employees and consultants in accordance with the JORC Code, using industry standard techniques and internal guidelines for the estimation and reporting of Ore Reserves and Mineral Resources. These estimates and the supporting documentation were reviewed by suitably qualified Competent Persons prior to inclusion here.
Competent Person’s Statement
The information in this website that relates to Exploration Targets, Exploration Results, Mineral Resources and Ore Reserves is based on data compiled by geologist, Dr Chris Giles, a Competent Person who is a member of The Australian Institute of Geoscientists. Dr Giles is a Director of the Company, a full-time employee and is a substantial shareholder. Dr Giles has sufficient experience, which is relevant to the style of mineralisation and type of deposit and activities described herein, to qualify as a Competent Person as defined in the 2012 Edition of “Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves”. Dr Giles consents to the inclusion in this website of the matters based on his information in the form and context in which it appears. Information for the Kalkaroo Ore Reserve and Mineral Resource and the Mutooroo Inferred cobalt and gold Mineral Resources complies with the JORC Code 2012. All other information was prepared and first disclosed under the JORC Code 2004 on the basis that the information has not materially changed since it was last reported. Havilah confirms that all material assumptions and technical parameters underpinning the reserves and resources continue to apply and have not materially changed.