ASX-listed gold producer in waiting, Horizon Minerals has tabled a revised open-pittable mineral resource estimate for the main gold deposits at its flagship Boorara gold project, about 15km east of Kalgoorlie. The updated measured, indicated and inferred resource now stands at 11.03 million tonnes of ore grading an average 1.26 grams per tonne for 448,000 ounces of contained gold. It comes after the Perth-based company’s recently completed contract trial mining and third-party toll processing program at Boorara generated $3.6 million in free cash flow.
Boorara has been subject to a swag of RC and diamond drilling over the past decade culminating in a previously estimated resource of 16.45 million tonnes of ore at an average grade of 0.96 g/t for 507,000 ounces of contained gold.
Horizon’s latest set of resource numbers factor in depletion following the trial mining and toll milling exercises.
The 11.03 million tonnes of ore at 1.26 g/t for 448,000 ounces of contained gold classified as amenable to open-cut mining goes down to 200 metres. Depth. As a comparison, the 2018 mineral resource estimate for Boorara in the top 200m was 15.62 million tonnes at 0.94 g/t for 474,000 ounces of gold.
Importantly, the reduction in tonnage has been somewhat offset by a 34 per cent increase in grade, which achieved the key aim of last year’s trial.
The Boorara project currently consists of the Royal, Regal and Crown Jewel deposits, with the new resource covering a strike length of more than 1.5km and widths of more than 250m.
It remains open along strike to the south and north and at depth with a significant quantity of unclassified material outside the current resource envelope, according to the company.
Boorara’s three deposits cornerstone Horizon’s five core satellite gold projects or deposits underpinning its proposed development of a stand-alone gold processing plant and production hub at the Boorara mine site.
Horizon says the $3.6 million in free cash flow from the trial mining and toll milling campaign enabled it to carry out an extensive evaluation of Boorara’s geology, mining parameters, metallurgy and processing parameters.
Some of the major findings and outcomes from the trial, pit mapping and grade control drilling included the presence of multiple flat lying quartz veins in addition to the main contact lode and excellent metallurgical performance.
According to the company, the inclusion of the cross cutting, flat lying vein arrays in the updated mineral resource estimate for Boorara has the potential to improve the economics of the project with a high metal content per vertical metre.
Horizon Minerals Managing Director, Jon Price said: “The highly successful trial has added to an extensive body of work completed at Boorara over many years. We now have a much greater understanding of the deposit, which will significantly de-risk the larger-scale development being assessed as part of the consolidated feasibility study.”
The company is contemplating an initial five-year mine plan for the overall Boorara gold operation, which it envisages will treat ore from Boorara, Jacques Find, Teal, Crake and other satellite deposits within trucking distance.
Horizon says the revised mineral resource estimate will go towards fine tuning the mine optimisation and design studies paving the way for the compilation of maiden ore reserves figures for Boorara.
The ore reserves will then be incorporated into the company’s consolidated feasibility study and economic models, and punters can look forward to the release of the feasibility study in the September quarter this year.
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By Matt Birney
