Rockhaven Announces Improved Metallurgical Test Work Results on its Klaza Project, Yukon Optimized Flowsheet has Potential to Reduce Capital and Operating Costs, Power Needs and Permitting Timelines
510 – 1100 Melville Street
Vancouver, BC V6E 4A6
604-687-2522
www.rockhavenresources.com
1 See Rockhaven news release dated June 21, 2018 for more information on the current mineral resource estimate for the Klaza deposit.
Rockhaven Announces Improved Metallurgical Test Work Results on
its Klaza Project, Yukon
Optimized Flowsheet has Potential to Reduce Capital and Operating Costs, Power Needs and
Permitting Timelines
May 6, 2024 - Rockhaven Resources Ltd. (TSX-V:RK) (“Rockhaven”) is pleased to announce
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
estimation1 update and planned future economic studies on the Klaza property.
Rockhaven’s comprehensive multi-year metallurgical program focused on several key objectives
which include d: (1) designing a simpler and more cost -effective processing flowsheet, (2)
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 highest 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.
“Flotation test work results, coupled with concentrate marketing analysis, has produced a
streamlined, conventional flowsheet yielding three concentrates, eliminating the need for onsite
pressure oxidation and its associated high capital and operating costs, electrical power needs and
permitting challenges,” stated Matt Turner, CEO of Rockhaven Resources. “ Furthermore, pre-
concentration results continue to offer options to positively impact mining and milling processes
and tailings management. Positive dense media separation results could allow larger scale mining
and reduce the processing cost of the run -of-mine mill feed , turning just below cut -off grade
mineralization into potential mill feed . It also assists us in meeting our tailings goal s, with the
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largest single product from the process now expected to be a crushed, benign coarse reject rather
than fine tailings, which is expected to significantly reduce the surface tailings storage needs of
the project.”
Geometallurgy and Flotation Test Work
The project has adopted a geometallurgical framework u tilizing 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 . I t 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. Table 1 shows the grades and recoveries to cleaned lead, zinc
and arsenopyrite concentrates from batch testing.
Table 1: Cleaned Concentrate Average Grades and Recoveries from MC-1
Average Concentrate Grades Average Recoveries
Mass Au Ag Pb Zn As Au Ag Pb Zn As
% g/t g/t % % % % % % % %
Lead 0.9 210 4,997 61.6 2.9 2.3 32 57 83 - -
Zinc 1.6 23 1,156 1.3 55.6 0.6 6 25 - 87 -
Arsenopyrite 2.2 112 112 0.5 0.7 30.0 44 3 - - 79
Project Wide Total: 82 85 83 87 79
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 nee ds, 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
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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.
The potential benefits of these DMS results include potential for a reduction in cut -off grades,
increased mill throughput and production rates, and a corresponding reduction in fine tailings as
compared to the 2020 PEA.
DMS recovery numbers from the main mineralized zones at Klaza are shown in Table 2 below:
Table 2: Results of DMS Test Work from Klaza Mineralized Zones
Mill Feed
in PEA Feed Grades Average Recoveries
t Au Ag Pb Zn Mass Au Ag Pb Zn
% g/t g/t % % % % % % %
Western BRX 32 7.9 92.2 0.60 0.68 50.0 99.0 98.4 97.4 94.7
Central Klaza 38 5.0 53.8 0.37 0.63 50.0 97.7 97.5 95.8 94.6
Western Klaza 11 1.7 99.1 0.24 0.19 32.8 78.9 89.3 92.2 81.6
Central BRX 19 0.7 25.5 0.23 0.37 50.0 94.2 96.9 98.2 96.6
Eastern BRX* 0 1.8 29.2 0.11 0.26 50.0 94.6 96.7 96.9 93.4
*Eastern BRX was not included in the 2018 Klaza mineral resource estimation and the 2020 Klaza Property PEA.
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 mineralised 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.
Summary and Next Steps
The above work has been done through an iterative process of extensive metallurgical testing in
conjunction with engineering, concentrate marketing and cost trade-off studies. The outcome has
resulted in the potential for a much lower metallurgical processing costs on a per tonne basis (as
compared to the 2020 PEA), driven primarily by the elimination of the on-site hydrometallurgical
circuit to treat the high -grade gold arsenopyrite concentrate that was contemplated in the 2020
PEA. Finally, the geometallu rgical model has significantly increased confidence in projected
metallurgical recoveries throughout the Klaza Property Mineral Resources, allowing for another
tier of project optimisation and de-risking that would hitherto have not been possible.
Next steps include locked-cycle test work and more in-depth geometallurgical analysis of the data
to be done in conjunction with the resource model and mine planning.
Qualified Persons
Technical information related to the metallurgical test program were provided and approved by
Chris Martin, C.Eng. an independent consultant and qualified person for the purpose of National
Instrument 43-101. All other technical information related to this news release has been approved
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by Matthew R. Dumala, P.Eng., a geological engineer with Archer, Cathro & Associates (1981)
Limited and qualified person for the purpose of National Instrument 43-101.
About Rockhaven
Rockhaven Resources Ltd. is focused on advancing its 100%-owned, camp-scale Klaza Property,
which hosts the Klaza Deposit and numerous lightly explored exploration targets. Rockhaven has
completed a mineral resource estimate and a preliminary economic assessment on the Klaza
deposit (see Klaza Property Technical Report with an effective date of July 10, 2020 and titled,
“Technical Report and Preliminary Economic Assessment Update for the Klaza Property, Yukon,
Canada.” which can be viewed at www.sedar.com under the Rockhaven profile or on the
Rockhaven website at www.rockhavenresources.com).
Matthew Turner
President, CEO and Director
Rockhaven Resources Ltd.
T:604-687-2522
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PROVIDER (AS THAT TERM IS DEFINED IN THE POLICIES OF THE TSX VENTURE
EXCHANGE) ACCEPTS RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF
THIS RELEASE.
Forward Looking Statements
Information contained in this news release contains forward-looking statements. These statements
reflect management ’s current estimates, beliefs, intentions and expectations; they are not
guarantees of future performance. Forward-looking statements are statements that are not
historical facts and are generally, but not always, identified by the words “potential”, “extensive”,
“simpler”, “de -risking”, “objective”, “optimized”, “reduce”, “streamlined”, “fuller”,
“conventional”, “high”, “encouraging”, “expect”, “future’, “positive”, “high”, “yield”
“comprehensive”, “significant”, “positive” “planned”, “optimize”, “interpreted” , “anticipates”,
variations of such words and similar expressions, or that events or conditions that “could”, “may”,
“should”, or “would” occur. Rockhaven cautions that all forward -looking statements are
inherently uncertain, and that actual performance may be affected by a number of material factors,
many of which are beyond the control of Rockhaven. Such factors include, among other things:
risks and uncertainties relating to exploration and development and the results thereof, including
the results of completed drill programs, their impact on the current mineral resource estimates and
existing and future economic studies; and the results of planned metallurgical and geotechnical
programs including the potential benefits of pre-concentration on higher and lower grade material
and cyanidation of pyrite concentrates ; the advancement of exploration targets through future
exploration; the outcome of the planned mineral resource estimate update and the planned
prefeasibility study , including the impacts of pre -concentration and whether or not such is
incorporated into the estimate and the study; the future marketability of concentrates; the ability
of Rockhaven to obtain additional financing ; the need to comply with environmental and
governmental regulations; fluctuations in the prices of commodities; operating hazards and risks;
competition; and other risks and uncertainties, including those described in Rockhaven’s financial
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statements available under the Rockhaven profile at www.sedar.com. Accordingly, actual and
future events, conditions and results may differ materially from the estimates, beliefs, intentions
and expectations expressed or implied in the forward -looking information. Except as required
under applicable securities legislation, Rockhaven undertakes no obligation to publicly update or
revise forward-looking information.