Press release from Marketwire
Rockhaven Announces BRX Zone Trench Grading 71.4 g/t Gold and 1,310 g/t Silver (97.60 g/t gold EQ) Over 2.25 m and Positive Metallurgical Results-Klaza Project, Yukon
Tuesday, October 08, 2013
Rockhaven Announces BRX Zone Trench Grading 71.4 g/t Gold and 1,310 g/t Silver (97.60 g/t gold EQ) Over 2.25 m and Positive Metallurgical Results-Klaza Project, Yukon08:30 EDT Tuesday, October 08, 2013
VANCOUVER, BRITISH COLUMBIA--(Marketwired - Oct. 8, 2013) - Rockhaven Resources Ltd. (TSX VENTURE:RK) ("Rockhaven") is pleased to announce the final 2013 excavator trench assays and preliminary gravity and bulk sulphide flotation metallurgical results from the Western BRX Zone on its 100% owned Klaza gold-silver property, located in the Dawson Gold Belt of southwestern Yukon.
News Release Highlights:
- Excavator trenching has successfully identified high-grade gold and silver mineralization within the Western BRX Zone with new exposures returning:
- 87.0 g/t gold and 768 g/t silver (102.36 g/t gold EQ) over 1.15 m in TR-47
- 71.4 g/t gold and 1,310 g/t silver (97.60 g/t gold EQ) over 2.25 m in TR-58
- 7.47 g/t gold and 537 g/t silver (18.20 g/t gold EQ) over 4.15 m in TR-59
- 31.38 g/t gold and 310 g/t silver (37.59 g/t gold EQ) over 3.55 m in TR-67
- 15.18 g/t gold and 301 g/t silver (21.20 g/t gold EQ) over 5.20 m in TR-73
- 31.20 g/t gold and 1,030 g/t silver (51.80 g/t gold EQ) over 2.25 m in TR-74
- 11.50 g/t gold and 1,680 g/t silver (45.10 g/t gold EQ) over 1.45 m in TR-75
- 34.70 g/t gold and 160 g/t silver (37.90 g/t gold EQ) over 3.00 m in TR-75
- 14.40 g/t gold and 729 g/t silver (28.98 g/t gold EQ) over 2.10 m in TR-77
- Preliminary sequential gravity and flotation tests on sulphide-bearing drill core from holes in this area produced excellent combined recoveries of 97.6% for gold and 98.3% for silver.
"We are very excited about the high-grade gold and silver results returned from recently completed trenches at the Western BRX Zone," stated Matt Turner, CEO of Rockhaven. "This focused program has better defined the controlling structure and will be followed up by aggressive diamond drilling in 2014 to delineate areas of high-grade gold and silver that were only partially outlined by previous widely-spaced drilling. The 2014 program will also target potential fault-offset extensions of this high-grade mineralization further to the west. Additionally, the preliminary metallurgical test results from 2012 drill core in holes down dip of the trenches demonstrates that most of the gold and silver should be recoverable through conventional flotation techniques."
The BRX Zone is a linear, mineralized structure that has exceptional lateral continuity. Gold and silver are hosted in veins emplaced alongside or in close proximity to a feldspar porphyry dyke. Systematic excavator trenching and diamond drilling by Rockhaven since 2010 has tested the BRX Zone with 39 trenches and 36 holes over a strike length of 2,400 m and to a maximum down-dip depth of 400 m.
Infill and step-out excavator trenching in 2013 at the Western BRX Zone confirmed continuity of the mineralized structure and further delineated areas of high-grade gold and silver that were partially outlined by widely spaced drill holes in 2011 and 2012. Previously announced diamond drill highlights from this area include DDH-12-96 which averaged 5.78 g/t gold and 111 g/t silver (8.00 g/t gold EQ) over 15.62 m (see Rockhaven news release dated October 2, 2012) and DDH-11-37 which returned 5.43 g/t gold and 50 g/t silver (6.43 g/t gold EQ) over 14.80 m (see Rockhaven news release dated November 2, 2011).
The best results are located along a 450 m section of the vein that is situated between two northeast trending off-set faults. The sense and magnitude of displacement along the westerly fault has not yet been determined, although mineralized structures have been identified on the more distal western side. Continued trenching and drilling across linear magnetic lows and soil geochemical anomalies in this area is planned for 2014 to target potential fault-offset extensions of high-grade mineralization at the BRX, Klaza and other zones.
Twenty-two excavator trenches tested the Western BRX Zone 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.
+ Represents the excavator trench sample length. True widths are estimated to be approximately 80-90% of the interval.
* Gold equivalence (EQ) 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 Western BRX Zone 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 Western BRX Zone using coarse reject material from 10 previously reported drill holes. This composite has a head grade of 7.02 g/t gold and 205 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 12.9% and 5.8%, 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 97.3% gold and 98.2% silver to a flotation concentrate, for a combined gravity/flotation recovery of 97.6% gold and 98.3% silver. Work continues to further upgrade the flotation concentrate through variation of rougher reagents, 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 Western BRX zone.
|Head Grade (g/t)*||7.02||205|
|Rougher Flotation Recovery||97.3%||98.2%|
|Rougher Concentrate Grade (g/t)||19.9||467|
|Combined Gravity & Flotation Recovery||97.6%||98.3%|
* Head grade determined by fire assay with AAS finish for gold (FAA303) and 4-acid digestion with AAS finish for silver (AAS42E).
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 at the road-accessible Klaza project consisted of approximately 5,000 m of excavator trenching in 38 trenches. It 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 metallurgical test work on composites from the Western BRX, Western Klaza, Eastern BRX and Eastern Klaza Zones is underway and results will be announced once finalized.
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.
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Rockhaven Resources Ltd.
CEO and Director