The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Rockhaven sees a mine emerging at high-grade gold-silver project in Yukon
Five years of systematic exploration has identified nine parallel zones rich in gold and silver at Rockhaven Resources Ltd.'s Klaza property in southern Yukon Territory that are beginning to look as if they may carry the size and grade to be developed into an economic mine.
In January, the junior published a maiden inferred resource estimate of 7.04 million metric tons grading 4.19 grams per metric ton (948,348 ounces) gold and 96.23 g/t (21.78 million ounces) silver for two of the zones.
This 1.31-million-ounce gold-equivalent resource does not take into account the 144.3 million pounds of zinc, 121.1 million lbs. lead and 14 million lbs. copper also contained in the drill delineated portion of the deposit.
"Attaining one million ounces of gold-equivalent was a key goal for our initial resource at Klaza," said Rockhaven CEO Matt Turner.
Achieving its initial goal, Rockhaven's 2015 program included a 56-hole drill program aimed at upgrading and expanding the resource, as well as carrying out engineering, metallurgical and environmental work that will be needed if a high-grade gold-silver mine is to be developed at this road-accessible project in southern Yukon Territory.
Strategic partner
To fund the 2015 exploration and development for Klaza, Rockhaven raised C$4.4 million in March.
The company's largest shareholder, Strategic Metals Ltd., scooped up all 21 million shares offered by the explorer. As a result, Strategic owns about 48.85 million Rockhaven shares, roughly 46.6 percent of the 104.84 million of the company's issued and outstanding shares.
Strategic Metals is a prospect generator with roughly 130 properties in its portfolio, most of them located in Yukon.
A group of five junior companies - Strategic, Rockhaven, ATAC Resources Ltd., Silver Range Resources and Arcus Development Group - belong to the Yukon-focused cooperative known as the Strategic Exploration Group.
In July, Strategic Metals swapped five properties located near Klaza (BBB, Sked-Desk, Dade, Queen and Nor) from its vast portfolio in exchange for five of Rockhaven's distal Yukon properties (Plata, Mount Hinton-Gram, Groundhog-Grayling-Cyr, Zap and Kluane-Ellias).
As a sweetener, Strategic paid Rockhaven C$250,000 in cash that the explorer used to consolidate other properties surrounding Klaza. All told, Rockhaven roughly tripled the size of the Klaza property to roughly 25,000 hectares (61,775 acres).
"Securing a much larger land position in the district is important for both continued exploration and logistical purposes, as Rockhaven advances the Klaza deposit toward development," Turner explained.
Growing Central Klaza
While the expanded land position gives Rockhaven a number of new exploration targets to investigate, the exploration company remains focused on the task at hand - developing the zones it has already identified at Klaza.
"We are excited to begin our fully-funded 2015 program which we expect will significantly expand the current high-grade gold and silver resources outlined within two of the nine main zones on the Klaza property. The drilling also will assess the potential at some of the seven other sub-parallel zones at which only broadly spaced drilling and trenching have been done," Turner said at the start of the program.
The nine parallel mineralized zones at Klaza are found within a 2,000- by 4,000-meter corridor. If lined up end to end, the strike of these zones has been traced for more than 9.4 kilometers (5.8 miles).
The maiden resource is contained within two of these zones, BRX and Klaza.
The majority of the 2015 drill program focused on expanding the high-grade gold and silver resource found in the main structure of the Central Klaza zone as well as subsidiary vein structures in the immediate hanging wall and footwall that were not included in the maiden resource.
Highlights include:
8.05 grams per metric ton gold, 272 g/t silver, 4.72 percent lead and 1.53 percent zinc over 1.39 meters of hole 243;
11.28 g/t gold, 75.9 g/t silver and 7.37 percent zinc over 3.68 meters of hole 258;
5.99 g/t gold and 165 g/t silver over 0.96 meters of hole 259;
5.2 g/t gold and 24.7 g/t silver over 2.08 meters of hole 261;
5.51 g/t gold, 141 g/t silver, 5.34 percent lead and 1.55 percent zinc over 2.95 meters of hole 265; and
9.46 g/t gold, 84.9 g/t silver, 1.83 percent lead and 2.68 percent zinc over 6.09 meters, and 11.29 g/t gold, 120 g/t silver, 1.15 percent lead and 7.93 percent zinc over 1.04 meters of hole 270.
"Drilling around the existing mineral resource at the Central Klaza Zone was one of the major focus (areas) of this year's exploration program," said Turner. "These intercepts better define the geological model in this part of the deposit and should expand the area of the mineral resource."
Southeastern expansion
Drilling also tapped multiple zones of mineralization in the southeastern portion of the drilled area at Klaza.
Hole KL-15-240 cut five gold-silver intercepts in three zones - Eastern BRX, Pika and an unnamed subsidiary structure. The best of these intercepts - 4.08 g/t gold and 63.5 g/t silver over 2.41 meters - was tapped in the Pika zone.
Hole Kl-15-245 cut numerous gold-silver intercepts across five zone, including 0.51 meters of 14.85 g/t gold and 101 g/t silver while cutting through the Eastern BRX zone.
Hole Kl-15-248 also cut numerous gold-silver intercepts across five zone, including 0.42 meters of 26.9 g/t gold, 576 g/t silver and 8.5 percent lead in the AEX zone.
"The veins in the southeastern part of the drill area at Klaza are relatively closely-spaced, which suggests potential for bulk tonnage mining," explained Turner. "These intercepts better define the geological model in this part of the deposit and should allow us to bring this mineralization into the mineral resource."
Toward development
After wrapping up the 13,738-meter drill program in late August, Rockhaven shifted its focus to engineering studies.
"Substantial progress is being made on geological and engineering fronts, which will be essential as the property moves toward development," Turner summarized.
Metallurgical work carried out this year outlined a preliminary flowsheet for Klaza that consists of lead flotation, followed by zinc flotation and then arsenopyrite-pyrite flotation. The arsenopyrite-pyrite concentrate is then pressure oxidized to liberate the gold and leached with cyanide. The overall flotation tails are also leached with cyanide.
This process is expected to recover 95 percent of the gold and 91 percent of the silver milled from the zones identified at Klaza.
"We're highly encouraged by these outstanding metallurgical results," Turner said. "Not only have recoveries increased substantially, we now have increased confidence that the same process works on all zones and at resource grades."
Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.
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