Horizon Minerals Ltd (ASX:HRZ) has completed an independent data review and concept study to evaluate the optimal pathway for its Nimbus Silver-Zinc Project 15 kilometres east of Kalgoorlie-Boulder in WA and adjacent to the company's Boorara Gold Project, amidst increasing demand for silver and zinc.
The concept study has confirmed the optimal economic pathway through mining the higher-grade lodes and producing a silver and zinc concentrate with more drilling required to increase overall tonnage and mine life.
A high-grade lode exists within this resource immediately below the historic Discovery pit and has a resource estimate of 260,000 tonnes grading 774 g/t silver for 6.4 million ounces and 12.8% zinc for 33,000 tonnes of zinc and there is also an exploration target that the company is aiming to firm up into further resources.
Moving forward, approvals are in place to advance the project to the next level of study and drill testing for additional high-grade tonnage at depth and along the Gretel-Nimbus-Brindabella trend.
Drilling is planned for the June and September quarters pending works approvals with the completion of a revised definitive feasibility study (DFS) expected in the March quarter of 2023.
“Potential to grow”
Commenting on the Nimbus Project, Horizon managing director Jon Price said: “With silver and zinc showing sustained price increases, we see the potential to grow the higher-grade core within the Nimbus resource at depth and along strike.
“The company will continue working to develop a longer-term production profile underpinning a concentrator at site and looks forward to further drilling success and the completion of the DFS.”
Increasing demand
Silver is currently trading at A$34 per ounce and zinc at A$5,200 per tonne with increasing demand forecast from the production of electronic devices, electricity transmission and photovoltaic cells used in electric vehicles and solar panels in addition to traditional wealth storage and galvanising.
The current global mineral resource estimate for Nimbus stands at: 12.1 million tonnes grading 52 g/t silver for 20.2 million ounces of silver and 0.9% zinc for 104,000 tonnes of zinc.
Notably, there is also a conceptual exploration target beneath the Nimbus pits inclusive of oxide silver and primary zinc-silver-lead sulphide mineralisation, of between 550,000 and 700,000 tonnes with a grade range of 3.4-3.6% zinc and 140-210 g/t silver, along with minor lead (0.45-0.65%).
A gold concentrate from the Horizon’s existing refractory ore at Teal Deeps, Jacques Find and Peyes Farm was also assessed which improved the life of mine and economics.
Indicative term sheets have been received from several potential offtake partners in Europe capable of smelting the complex metallurgy of the concentrate.
Review summary
Horizon completed a strategic review of the Nimbus Silver-Zinc project in 2021 and elected to retain the project on a 100% basis.
An independent review by consultancy firm Australian Mining Consultants (AMC) and Sedgmen was commissioned to assess the historic data, mine optimisations and metallurgical work to evaluate the optimal pathway forward for the project.
The review highlighted the potential of the project through underground mining the fresh higher-grade ore below the historic Discovery pit and generating silver and a zinc concentrate for sale to potential offtake partners.
A gold concentrate was also assessed to improve the overall life of mine given the need for additional tonnage to underpin a concentrator at the site.