Thor Mining (LSE:THR) inched up 1.8pc to 0.8p on Tuesday morning after announcing the successful recovery of gold from its Kapunda copper project. In what was described as an ‘unexpected bonus’ by executive chairman Mick Billing, Thor said the precious metal was recovered from historical drilling samples at the South Australia-based asset.

The actual percentage recovery of gold extracted could not be determined accurately in this round of work. However, Thor said the concentrations of the metal in solution indicates that gold extraction does occur at Kapunda. The firm will now carry out further test work to quantify gold recovery, with results for 28 historical surface and drill core samples reportedly boasting grades of between 0.93g/t to 8.58g/t.

Critically, Thor said the results demonstrate proof of concept at Kapunda using techniques appropriate for in situ recovery (ISR) test work. It added that this enhances its successful recovery of copper using ISR appropriate test work at the project in December.

ISR or solution mining has a lower environmental footprint than conventional mining with little visual impact and minimal infrastructure required. The process accelerates what is naturally happening within the bedrock and water table and, until recent advances in technology, had limited applications in mineral extraction.  

It is now possible to apply the ISR method of extraction to copper and gold resources that were previously un-minable. During the process, a benign solution is pumped into bores drilled into the ore body to dissolve the copper. The copper-containing solution is then pumped to a recovery plant to extract the metal from the liquid.

The In-situ Recovery (ISR) process

Kapunda, which is based around 90km from Adelaide, is suitable for ISR since it is a shallow resource found in an area with a high water table. The asset is primarily a copper project, with an inferred JORC resource estimate of 47.4MMts grading 0.25pc of the metal. This is equal to 119,000ts of contained copper considered amenable to ISR techniques.

Thor currently has exposure to the project through its agreement to earn up to 60pc of a private Australian business called Environmental Copper Recovery (ECR). ECR has, in turn, entered a deal with Terramin Australia to earn, in two stages, up to 75pc of the rights over metals that may be recovered at Kapunda. Last month, Thor announced plans to merge ECR with another business called Environmental Metals Recovery to form a new company called EnviroCopper.

In Tuesday’s update, Billing said there is not yet sufficient drilling assay information to allow a gold resource to be added to Kapunda’s previously-published copper resource. However, he said that its latest results could potentially represent a ‘very significant project enhancement’.

‘The information we have suggests the presence of gold relatively evenly across much of the Kapunda deposit,’ he added. ‘The directors of ECR and the directors of Thor are reviewing options in light of this new and potentially strategically critical information, and will provide further updates in the near term.’

Busy period

Tuesday’s news comes at a busy time for Thor. Towards the end of last month, the company announced plans to expand its operational portfolio through two acquisitions. The business is looking to acquire Pilbara Goldfields and Hammersley Metals, which collectively hold interests in two granted licences and seven licence applications at various stages of advancement. These assets are prospective for gold and uranium and cover a total of 764km2 in the Pilbara region of Western Australia and the Northern Territory of Australia.

Thor said it has chosen to pursue the opportunities – which will cost it around £450,000 - because much of its portfolio is beginning to reach the crystallisation stage. Indeed, alongside the divestment of Kapunda, the business has advanced its 100pc-owned Molyhil tungsten and molybdenum project to mine construction-ready status. It is currently in a commercialisation process to secure project-level finance for the mine construction phase.

Once these two transactions have completed, Thor said its exploration interests will be limited to its 40pc-owned Bonya tungsten, copper, and vanadium project. As such, Billing said the new firms will give Thor access to a new round of exploration opportunities in Australia.

Author: Daniel Flynn

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