Results from the first seven infill holes for 766 metres have been positive, confirming substantial thicknesses of cobalt mineralisation consistent with the existing geological model.
They include 68 metres at 1218ppm cobalt, 13.4% iron and 13.4% sulphur from 116 metres, and 52 metres at 1042ppm cobalt, 11.1% iron and 11.2% sulphur from 93 metres.
As at November 30, 5,788 metres had been completed, including 1,353 metres of diamond drilling and 4,435 metres of reverse circulation (RC) drilling.
The planned total of more than 15,000 metres is the largest single drill campaign undertaken at the project.
Initial drilling is focused on the Pyrite Hill deposit, which represents 36% of the existing 72 million tonne mineral resource and about 39% of the contained cobalt inventory of 61,500 tonnes.
Cobalt Blue’s chairman Rob Biancardi said: “We are pleased by recommencement of drilling at Thackaringa.
“Assays received to date have affirmed continuity of high-grade cobalt mineralisation at the Pyrite Hill deposit with further potential for resource growth identified through down-dip extension.”
Other strong results are 56 metres at 824ppm cobalt, 11.1% iron and 9.4% sulphur from 146 metres, and 91 metres at 826ppm cobalt, 12.8% iron and 10.2% sulphur from 67 metres.
Visible mineralisation in drill core from a diamond hole at Pyrite Hill deposit.
The Thackaringa Cobalt Project is about 25 kilometres west-southwest of the mining centre of Broken Hill and comprises four tenements for a total area of 63 square kilometres.
The existing resource estimate is based on three large tonnage cobalt-bearing pyrite deposits – Pyrite Hill, Railway and Big Hill.
Priority exploration targets identified from heliborne electromagnetic survey.
Two diamond and two RC rigs deployed
A versatile drilling fleet comprising two diamond and two RC drill rigs has been deployed to service program objectives.
The initial component of the drilling campaign is focused on completing infill drilling to provide greater confidence in the resource classification and to better define the oxidation layers which cap fresh sulphide mineralisation.
Diamond drilling assays received reflect intersections from shallow drill holes directly targeting the oxidation zone.
The intersections comprise variable zones of sulphide mineralisation intercalated with localised oxidation which is characterised by partial sulphide/cobalt depletion.
This material was not included in the March 2018 mineral resource estimate.
Core samples from the current campaign will be retained for metallurgical test work to determine if cobalt can be recovered from this type of oxidised material.
High-grade pyrite mineralisation intersected during the drilling campaign.
On completion of drilling at Pyrite Hill, all rigs will be deployed to the Railway deposit for completion of the planned program.
Project water supply confirmed
Cobalt Blue has also confirmed the annual availability from Essential Water of 1.2 gigalitres (GL) of water without any upgrade to the utility’s trunk main at a metered take-off point on the western outskirts of Broken Hill.
An additional 0.3 GL per annum is available if COB provides a capital contribution to increase the trunk main capacity.
Essential Water notes that the water supply will soon be from a more reliable source on the Murray River at Wentworth via a newly constructed pipeline.
The process plant water balance developed in the project’s pre-feasibility study identified a water supply requirement of 1.22 GL per annum, which included a 5% allowance for evaporation.
With a 20% contingency, the processing water supply requirement is 1.5 GL per annum.
Meets processing demands
COB believes that securing a reliable source of high-quality water that meets the processing requirements at the Thackaringa Cobalt Project is a significant milestone.
The company’s chief executive officer Joe Kaderavek said: “COB is excited to secure a reliable source of water that meets the processing demands of the project.
“We look forward to working with Essential Water to develop the provision of water to the site.”