Wednesday saw Thor Mining (LSE: THR) show further evidence of its part-owned Kapunda project’s full gold potential. The business said EnviroCopper – which has entered a two-stage agreement to earn a 75% stake in Kapunda – has become aware of a public document that contains the findings of IP surveys on the South Australian asset. This work suggests that targets for Kapunda-style mineralisation extend up to 4.5km south of the known Kapunda resource.
The news comes less than a month after Thor – which holds a 25pc interest in EnviroCopper with rights to increase to 30pc – revealed positive drilling progress at Kapunda. Kapunda drilled three holes and installed two screened wells to complete initial hydrogeological investigations at the asset.
Not only did this work reveal that the project’s water table is quite shallow, but it also confirmed connectivity between screened intervals along its predominant fracture directions. These are both critical requirements for the ISR process, which centres around a chemical process called ‘leaching’. In layman’s terms, this involves dissolving minerals underground in a solution before extracting them at the surface. As ISR is much cheaper and quicker than actually building a copper mine, EnviroCopper believes that the technique can bring lower-grade projects into economic territory.
Elsewhere, Thor said the first round of drilling at Kapunda had revealed that the fracture zone contains significant copper mineralisation thought to be amenable to the ISR process. Indeed, the pilot hole encountered 66m at 0.27pc copper including 5m at 0.72pc copper and 11m at 0.54pc copper. Meanwhile, the two additional holes intersected 8m, 23m at 0.49pc copper to end of hole and 22m, 6m at 0.47pc copper to end of hole respectively.
EnviroCopper’s next stage of work includes large-scale column leach recovery tests leading on to a full-scale field trial.
By achieving production at Kapunda, EnviroCopper hopes to demonstrate ISR’s operational viability in the copper market and take the technology to other projects. Aided by historical mining data and environmental and hydrogeological work, EnviroCopper has estimated Kapunda contains an ISR-amenable inferred copper resource of 119,000ts.
As announced in April, the company has also been able to recover gold from samples taken from the project and work to ascertain whether it can establish a resource for the precious metal is ongoing. Before commercialisation, EnviroCopper must complete a pre-feasibility study and a definitive feasibility study at Kapunda. It will also have to meet any necessary environmental, social, and regulatory requirements and secure financing. Handily, its $2.8m government-issued research grant will support it in these efforts- indeed, the firm expects these funds to take the project through to demonstration of feasibility.
On Wednesday, Thor’s executive chairman Mick Billing elaborated on Kapunda’s potential when he said: ‘The momentum behind the Kapunda project continues to develop, particularly as its emerging gold potential is recognised. We look forward to assays from the recent program of drilling and pump testing at Kapunda to add further weight to the story.
‘In addition to the existing schedule of developing the feasibility of ISR production at Kapunda from the existing published resource estimate, substantial potential is emerging to extend and add to this, as well as potentially quantifying the gold mineralisation and we look forward updating investors on the strategy for this in the near term.’
Once progress has been made at Kapunda, EnviroCopper will move on to Moonta – its second 75pc-held project. Moonta is located around 160km north-east of Adelaide within the historical copper triangle of South Australia, where around 300,000ts of copper were mined and processed between the 1860s and 1920s. Although it is an earlier-stage project than Kapunda, Moonta is also thought to be a much larger opportunity.
In August 2019, EnviroCopper announced an initial inferred resource estimate for the asset of 66.1MMts grading 0.17pc copper. This translates to 114,000ts of contained copper considered amenable to ISR, taking EnviroCopper’s business-wide managed resource inventory 233,000ts.
This initial figure was formed from the analysis of just 164 drill holes at Moonta that led to the identification of three copper deposits, called Wombat, Bruce, and Larwood. A further 308 holes already drilled over these deposits will feature in future resource modelling once quality assurance has been completed, providing an obvious opportunity for upside. What’s more, all three deposits remain open along strike or at depth – providing EnviroCopper with a chance to identify mineralisation beyond that already discovered.