Rockhaven Resources Ltd. announced the results of recent extensive metallurgical and pre-concentration test work at its 100%-owned and road accessible Klaza property, located in southern Yukon. This test work was completed on composites from drill core representing zones that are the focus of an upcoming Mineral Resource estimation update and planned future economic studies on the Klaza property. The company's comprehensive multi-year metallurgical program focused on several key objectives which included: designing a simpler and more cost-effective processing flowsheet, maximizing precious and base metal recoveries to saleable concentrates, and (3) exploring ways to limit the production of fine tailings and hydrometallurgical products that need special management.

The work has been largely executed at Blue Coast Research under the guidance of Chris Martin, Independent Consulting Metallurgist, and Rockhaven's Technical Committee. Highlights from this news release include: Gold recoveries of 82% and silver recoveries of 85% were obtained using conventional flotation, producing three marketable concentrates for shipment to smelters, from the composite that is most representative of the majority of the current Klaza Mineral Resources; The lead concentrate, which has the value of the three concentrates, returned assay grades averaging 210 g/t gold, 4,997 g/t silver and 61.6% lead; The arsenopyrite concentrate returned average grades of 112 g/t gold and could be shipped off-site to a smelter; and, Dense media separation test work returned high metal recoveries to a 50% mass pull and is expected to be included in future mineral resource and economic studies. Geometallurgy and Flotation Test Work: The project has adopted a geometallurgical framework utilizing almost all of its recent testing, where data has been gathered from 75 samples located throughout all the mineralized zones included in the current Klaza Property Mineral Resources.

This work provided a fuller understanding of the metallurgical response of materials throughout the different mineralized zones and substantially reduces metallurgical risk to the project, allowing for better mine planning and more accurate production forecasting. It is also expected to yield a more robust financial model for the project. Variability flotation test work was completed on 28 composites, built using the initial 75 samples collected, which were then grouped into three Master Composites (MC-1, MC-2, and MC-3) based on their metallurgical response.

Master Composite-1 (MC-1) consists of the most representative material from the majority of the Klaza Mineral Resources, and includes the Western BRX, Central Klaza and Western Klaza zones. Refractory Gold Flotation: Recent testing, combined with concentrate marketing efforts, has established that flotation would allow for the creation of a high-grade and marketable arsenopyrite concentrate containing most of the refractory gold. This arsenic-rich product attracts penalties and fees for processing the arsenic, but the gold grades are high enough to ensure these concentrates should return sufficient revenue after treatment charges to make them competitive economically with on-site processing.

This would eliminate the need for on-site pressure oxidation and hydrometallurgy, greatly simplifying the metallurgical flowsheet, reducing permitting risk and power needs, and could potentially reduce capital costs as compared to the 2020 Preliminary Economic Assessment (2020 PEA). Pre-concentration and Tailings: Rockhaven announced pre-concentration results using XRT-Sorting technology on September 12, 2023. Further test work, using gravity pre-concentration via dense media separation (DMS) as opposed to XRT-Sorting, has increased the recoveries at similar mass pulls from four of the five main zones, rejecting 50% or more of the run-of-mine feed material as a barren, coarse crushed product.

Furthermore, flotation test work on the minor amounts of gold and silver which reported to the DMS tails were shown to be unrecoverable to a potentially marketable product, so the net loss of recoverable metal from this pre-concentration step is negligible. Pyrite Flotation and Concentrate Cyanidation: Pyrite flotation from the arsenopyrite flotation tails, and cyanide leaching of this concentrate, offers potential to increase gold recoveries by a further 2-4%. However, the value of this added step varies widely with different mineralized materials in the current mineral resource, so further geometallurgical work is needed to confirm whether this step is warranted and, if so, for which mineralized zone.