September 24, 2013 - Rockhaven Resources Ltd.
(TSX-V:RK) (“Rockhaven”) is pleased to announce the initial 2013 excavator trench assays and preliminary gravity and bulk sulphide flotation metallurgical results from one of eight known mineralized zones on its 100% owned Klaza gold-silver property, located in the Dawson Gold Belt of southwestern Yukon.News Release Highlights:
- Excavator trenches have successfully confirmed continuity of the Central and Western Klaza Zones with new high-grade exposures returning:
- 5.61 g/t gold and 300 g/t silver (11.61 g/t gold EQ) over 18.79 m in TR-51
- 16.20 g/t gold and 158 g/t silver (19.36 g/t gold EQ) over 6.84 m in TR-52
- 25.70 g/t gold and 449 g/t silver (34.68 g/t gold EQ) over 2.27 m in TR-66
- 8.29 g/t gold and 295 g/t silver (14.20 g/t gold EQ) over 4.60 m in TR-69
- 16.76 g/t gold and 1052 g/t silver (37.80 g/t gold EQ) over 3.03 m in TR-70
- Preliminary sequential gravity and flotation tests on sulphide-bearing drill core from holes in this area produced high combined recoveries of 97.3% for gold and 99.0% for silver.
“Detailed excavator trenching at the highly prospective Central and Western Klaza Zones has identified priority near-surface drill targets for 2014,” stated Matt Turner, CEO of Rockhaven. “Also, we are highly encouraged by the preliminary metallurgical test results, which suggest gold and silver should be recoverable through conventional flotation techniques.”Klaza Zone
The recently completed excavator trenching has increased the known strike length of the Klaza Zone to 2,400 m. The zone hosts three distinct styles of gold and silver mineralization along its length. The Western Klaza Zone consists of discrete veins that tend to be higher grade than those observed further to the east and is considered to be a high-grade underground target. The Central Klaza Zone comprises a system of veins, breccias and sheeted veinlets that are prospective for selective extraction by open pit methods. The Eastern Klaza Zone is characterized by sheeted vein complexes and surrounding alteration envelopes, which coalesce to form 20 to 100 m thick mineralized bands. These bands are being assessed as potential bulk tonnage targets and will be further discussed in a later news release once all 2013 assays are received and interpreted.
Infill and step-out trenching in 2013 at the Central and Western Klaza Zones confirmed continuity of the mineralized structure and further delineated areas of high-grade gold and silver that were partially outlined by widely spaced trenches and drill holes in 2011 and 2012. Additionally, two northeast trending off-set faults have been identified that may be important in locating the open western extensions of the Klaza Zone and the other mineralized structures identified on the property.
A total of eight excavator trenches targeted this area in 2013, and the most significant assay results are shown in the table below. Maps showing the locations of the trenches and nearby drill holes can be viewed on Rockhaven’s website at www.rockhavenresources.com
º Represents the excavator trench sample length. True widths are estimated to be approximately 80-90% of the interval.
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*Gold equivalence has been calculated using metal prices of $1300 per ounce gold and $26.00 per ounce silver, to be consistent with earlier calculations. It assumes 100% recoveries.Preliminary Sequential Gravity and Bulk Sulphide Flotation Test Results
Preliminary mineralogical and scoping level metallurgical tests are currently being conducted on sulphide-bearing drill core from the Central and Western Klaza Zones to investigate mineral associations and evaluate potential concentration and recovery methods. Both test programs are being carried out by SGS Mineral Services at its laboratory in Vancouver, British Columbia.
A single composite was designed to represent typical sulphide mineralization from the Central and Western Klaza Zones using coarse reject material from 15 previously reported drill holes. This composite has a head grade of 5.06 g/t gold and 290 g/t silver. Gold and silver deportment and quantitative mineralogy results show that gold largely occurs as native gold or electrum, with a high degree of liberation. Silver mainly occurs with pyrargerite, tetrahedrite and electrum, which are also well liberated from gangue and non-ore sulphide minerals. Mineralogy was investigated using the widely recognized quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) technique.
Standard E-GRG (Gravity Recoverable Gold) tests were performed using three stages of sequential separation. Results of the E-GRG tests suggest minimal gold and silver can be recovered by gravity, with recoveries of 13.4% and 5.7%, respectively.
Follow-up flotation testing investigated the potential to obtain a precious-metal rich bulk sulphide concentrate. Initial rougher flotation tests conducted on the gravity tailings showed recoveries of 96.8% gold and 98.4% silver to a flotation concentrate, for a combined gravity/flotation recovery of 97.3% gold and 99.0% silver. Work continues to further upgrade the flotation concentrate through cleaner flotation tests, evaluation of the impact of finer grind sizes, and investigation of sequential flotation of sulphides. Results from this ongoing test program will be released as they become available.
The following table summarizes the metallurgical results returned to date from the composite of samples from the Central and Western Klaza Zones.
*Head grade determined by fire assay with AAS finish for gold (FAA303) and 4-acid digestion with AAS finish for silver (AAS42E).
|Head Grade (g/t)*|
|Rougher Flotation Recovery|
|Rougher Concentrate Grade (g/t)|
|Combined Gravity & Flotation Recovery|
There is currently no mineral resource at the Klaza property. Recovery values are from initial metallurgical test work and do not include potential optimizations.2013 Exploration Program
The 2013 field program is now completed at the road-accessible Klaza project. It consisted of approximately 5,000 m of excavator trenching in 38 trenches that focused on extending and confirming continuity within the Klaza and BRX Zones as well as discovering new mineralized zones in other areas of the property that have not been systematically explored to date. Results from the remaining 30 trenches will be released on a target by target basis once assays are received, compiled and evaluated.
All significant assays from 2010, 2011, 2012 and 2013 diamond drilling and excavator trenching can be viewed on the Company’s website (www.rockhavenresources.com
), including geological maps, cross-sections and assay histograms.
Trench samples included in this press release were processed in 36 sample batches with each batch including two assay standards, two blank samples, and a coarse reject duplicate. Analytical work was done by ALS Minerals with sample preparation in Whitehorse and assays and geochemical analyses in North Vancouver. All samples were routinely analyzed for gold by fire assay followed by atomic absorption (Au-AA24) and 48 other elements by four acid digestion (ME-MS61). All overlimit values were determined for gold by fire assay and gravimetric finish (Au-GRA22) and for silver using Ag-OG46 and Ag-GRA21). All gold and silver grades reported in this release were calculated from the assay results. All standard, blank and duplicate samples passed QAQC reviews.
The 2013 program was managed by Archer, Cathro & Associates (1981) Limited (Archer Cathro). Technical information in this news release has been approved by Matthew R. Dumala, P.Eng., a geological engineer with Archer Cathro and qualified person for the purpose of National Instrument 43-101.
Rockhaven Resources Ltd. is a well-managed gold and silver exploration company focused on growth through advancing its quality portfolio of wholly-owned projects. For additional information concerning Rockhaven Resources Ltd. or its various exploration projects please visit Rockhaven’s website at www.rockhavenresources.com
Matthew Turner, CEO and DirectorRockhaven Resources Ltd.
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