Rockhaven Announces Positive Metallurgical Results from its Klaza Project, Yukon
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Rockhaven Announces Positive Metallurgical Results from its Klaza Project, Yukon
April 19, 2018 - Rockhaven Resources Ltd. (TSX-V:RK) (“Rockhaven”) is pleased to
announce positive results from ongoing metallurgical test work on several of the
mineralized zones at its 100% -owned and road accessible Klaza property, located in the
Dawson Range Gold Belt of southern Yukon. These zones will be the focus of an
updated Mineral Resource es timate that will include approximately 20,000 m of
additional expansion and in-fill diamond drilling that were completed in 2016 and 2017.
Highlights from this press release include:
Gold recoveries of 82% were obtained by flotation and cyanide leaching in the
Eastern BRX Zone, using equipment already envisioned in the March 2016
PEA. The more than 300,000 ounces of gold estimated in this zone were not
included in the PEA due to metallurgical uncertainties. Considerable economic
and exploration upside e xists across this zone and within this portion of the
project area;
The Eastern BRX, Western BRX and Central Klaza zones responded very well
to pre -concentration test work. Using Dense Media Separation, the average
gold grades more than doubled, with gol d recoveries ranging from 87.0 to
98.2%; and,
The revised Mineral Resource estimate is progressing well and will be complete
by late May or early June.
“We are extremely excited about the opportunities provided by the results of this test
program, which should greatly benefit overall Klaza project economics,” stated Matt
Turner, CEO of Rockhaven Resources. “The pre -concentration results and encouraging
recoveries from the Eastern BRX Zone are potential game -changers for the project,
allowing lower cut -off grades to be considered and the inclusion of the Eastern BRX
Zone in future economic studies. The Klaza and BRX zones are fully open to the east
and, with the positive metallurgical results, will be a major focus of future exploration
programs.”
The Klaza project hosts a large hydrothermal system that is concentrated within a 4 km
long by 3 km wide structural corridor, which has only been tested to a maximum depth of
450 m. Eleven known mineralized zones have been identified within this corridor and al l
are open for expansion along strike and to depth.
The eastern portion of the project area comprises multiple, sub-parallel veins, that include
the Eastern Klaza, Eastern BRX, Pika, Stroshein, and part of the AEX zones , all of
which are open to the east, towards the mostly untested Kelly Porphyry. Due to the
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limited drilling in this area of the project, only the Eastern BRX and the Pika zones were
included in Rockhaven’s December 2015 Mineral Resource Estimate.
The Eas tern BRX Zone currently hosts an Inferred Mineral Resource estimate of
2,406,000 tonnes containing 317,000 oz gold and 4,127,000 oz silver at an average grade
of 4.10 g/t gold and 53 g/t silver (See March 1, 2016 Technical Report on the Rockhaven
website ( www.rockhavenresources.com)). Previous flotation test work in the Eastern
BRX Zone performed poorly, and did not produce saleable concentrates. Because of this,
Mineral Resources in the Eastern BRX Zone were not included in the March 2016
preliminary economic assessment (PEA).
Metallurgical Test Program
The metallurgical test program is evaluating opportunities to optimize and simplify the
flowsheet utilized in the March 2016 PEA through the addition of pre-concentration prior
to milling; and investigating alternative low -cost processing options for the Eastern BRX
Zone.
The current test program on run -of-mine material began with direct cyanide leaching,
with subsequent work testing flotation and leac hing. Good performance was observed in
both scenarios, with 81% and 82% of the gold being recovered to doré by direct leaching,
and leaching and flotation, respectively. The following table summarizes performance of
the combined flotation and leaching flow sheet. Two stages of flotation were conducted,
with a lead rougher, followed by cleaning, and a sulphide rougher.
Product Mass Grade Distrib. CN Rec. Overall Rec.
% Au (g/t) Au (%) Au (%) Au (%)
Pb Cleaner
Concentrate 1.39 114.1 66.6 98.6 65.7
Pb Cleaner Tails 3.96 1.66 2.76 71.3 2.0
Sulphide Rougher
Concentrate 16.17 3.90 27.3 51.4 14.0
Final Tails 78.49 0.09 3.38 0.0 0.00
Total 81.7
Pre-concentration test work was conducted on half-core material from the Western Klaza,
Central Klaza, Western BRX and Eastern BRX zones. Four composites were blended,
representing each zone, and were crushed to 3/8”. Dense Media Separation (DMS) was
used to evaluate pre-concentration response, at a separation Specific Gravity of 3.05. The
following table s hows a summary of the DMS results, with the concentrate representing
the sink fraction and fines (< 1.18 mm) combined.
Comp
Head Grade Mass Pre-Concentrate Grade Recovery (%)
Au
(g/t)
Pb
(%)
Zn
(%)
S
(%) (%)
Au
(g/t)
Pb
(%)
Zn
(%)
S
(%) Au Pb Zn S
EBRX 1.88 0.10 0.27 6.79 32.5 5.01 0.27 0.74 16.09 87.0 88.8 89.5 77.5
WBRX 7.25 0.76 0.91 8.48 45.3 15.73 1.59 1.86 17.22 98.2 71.8 76.9 67.8
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WKZA 1.45 0.27 0.24 4.07 24.5 3.80 0.84 0.79 2.31 64.7 66.8 81.2 93.2
CKZA 3.59 0.34 0.67 4.14 34.5 9.41 0.86 1.66 9.29 90.9 68.3 67.6 61.7
Significant upgrading by DMS was achieved, with good recoveries in all zones aside
from Western Klaza, where the vein contains more sulphosalts and lesser amounts of
sulphide minerals. Work is underway to perform bulk DMS followed by locked cycle
flotation testing to evaluate performance of the overall flowsheet.
Exploration Potential
It is highly encouraging that all parts of the known Klaza d eposit now respond well to
metallurgical test work. It is particularly encouraging that many areas respond to simple,
low-cost methods that could enable higher production rates. Within the known Klaza
hydrothermal system, only the near surface areas of t he Central Klaza, Western BRX and
Western Klaza zones have been thoroughly explored to date.
The results of the metallurgical test work in this news release highlight multiple priority
targets for future exploration. Three of the most important targets, given their proximity
to the known deposits, are: 1) a number of new discoveries to the north of the Klaza Zone
made in 2017; 2) the eastern projection of the Eastern BRX Zone; and 3) the Eastern
Klaza Zone, which is mineralogical similar to the Eastern BR X Zone, but has only been
tested by widely spaced diamond drill holes.
Updated Mineral Resource Estimate
An updated Mineral Resource estimate for the Klaza property is being prepared by AMC
consultants and is anticipated to be complete in late-May to early-June. In preparation for
the estimate, the Klaza and BRX zones were remodeled to incorporate approximately
20,000 m of additional diamond drilling comple ted in 2016 and 2017. The new estimate
will utilize revised cut -off grades that reflect results from the 2018 metallurgical test
program and include lower grade mineralization in the hanging walls and footwalls of the
main veins, which was not modelled in the previous resource estimate.
Qualified Persons
Results for the metallurgical test program were provided and approved by Chris Martin,
C.Eng., of Blue Coast Metallurgy Ltd. a qualified person for the purpose of National
Instrument 43 -101. All other t echnical information in this news release has been
approved by Matthew R. Dumala, P.Eng ., a geological engineer with Archer, Cathro &
Associates (1981) Limited and also a qualified person for the purpose of National
Instrument 43-101.
About Rockhaven
Rockhaven Resources Ltd. is a mineral exploration company focused on growth through
the advancement of its Klaza project. For additional information concerning Rockhaven
or its Klaza project please visit Rockhaven’s website at www.rockhavenresources.com.
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Matthew Turner
President, CEO and Director
Rockhaven Resources Ltd.
T:604-687-2522
NEITHER THE TSX VENTURE EXCHANGE NOR ITS REGULATION SERVICES PROVIDER (AS
THAT TERM IS DEFINED IN THE POLICIES OF THE TSX VENTURE EXCHANGE) ACCEPTS
RESPONSIBILITY FOR THE ADEQUACY OR ACCURACY OF THIS RELEASE.
This news release may contain forward looking statements based on assumptions and j udgments of
management regarding future events or results that may prove to be inaccurate as a result of exploration
and other risk factors beyond its control, and actual results may differ materially from the expected results.