The mining newspaper for Alaska and Canada's North
The mining newspaper for Alaska and Canada's North
Good gold grades from Peak zones drilling overshadowed by remarkable ones
High-grade skarn mineralization drilled at the Main Peak zone.
Peak Gold is raising the bar for high-grade gold deposits in Alaska. In fact, the gold grades this joint venture has reported from summer drilling at its Tetlin project in eastern Interior Alaska are so remarkable that near-surface, minable widths of quarter-ounce-per-metric-ton-gold cut at the project's Peak zones are overshadowed by numerous 13-meter-plus intercepts of more than 1.5 oz./t gold.
One such example of this eclipsing effect can be found in TET16272, one of 19 holes included in the latest batch of assay results from summer drilling in the three Peak zones – Main, North and West.
Drilled into the heart of the North Peak zone, TET1672 cut multiple gold zones that included 2.43 meters grading 7.04 grams (0.226 troy ounces) per metric ton gold from a depth of 14.33 meters. While this near surface intercept would typically make the highlights reel, it gets lost in the shadow of two longer and higher grade intercepts encountered deeper in the same hole: 9.83 meters of 49.01 g/t (1.58 oz/t) gold from 23.13 meters and 7.96 meters of 15.99 g/t (0.514 oz/t) gold from a depth of 43.09 meters.
While these zones of high-grade gold are impressive in their own right, TET16272 was not the best of the holes drilled this summer. Three other holes targeting the high-grade heart of North Peak cut even longer lengths with gold grades topping 1.5 oz/t.
Skarn deposits such as the Peak zones are formed when metal-laden magmatic fluids contact carbonate-enriched sandstones, causing the metals to quickly drop out. While these deposits are known for their high-grade concentrations of gold, silver, copper and other metals, their geometry is often irregular and tough to predict.
Peak Gold's ability to target and hit these high-grade gold zones is a testament to its exploration team's understanding of the geology of the Peak zones, as well as the robustness and continuity of these skarn deposits.
Expanding gold, confidence
The summer program at Tetlin is the second phase of 2016 drilling completed by Peak Gold, a limited liability joint venture formed by Royal Gold Inc. and Contango Ore Inc. at the beginning of 2015.
Royal Gold, which is the operator of the JV, can earn up to a 40 percent interest in Tetlin by investing US$30 million in Contango Ore's 735,000-acre underexplored project by October 2018.
At the time the JV was formed, Main Peak hosted the equivalent of 1.2-million ounces of gold, when accounting for the value of the copper and silver present in this most advanced zone at Tetlin.
In its first year as a Peak Gold partner, Royal Gold invested US$6.8 million in a 2015 exploration program that expanded the breadth and depth of the Main Peak deposit and Peak North, a seemingly parallel zone of mineralization with similar grades and thicknesses about 250 meters to the north.
Excited about the discoveries made in 2015, Royal Gold upped the ante, depositing US$11 million in the Peak Gold bank account to fund a 2016 exploration program that has focused primarily on expanding North Peak.
The impressive grades from a 19-hole initial phase of 2016 drilling launched in February began to reveal a deposit at North Peak with the size and tenor to rival Main Peak.
Highlights from this phase-1 drilling include:
• TET16192 cut six mineralized intercepts at North Peak, including 13.27 meters averaging 49.19 g/t (1.58 oz/t) gold from a depth of 78.5 meters;
• TET16206, drilled about 75 meters west of hole 192, cut 43.43 meters of 3.61 g/t gold from a depth of 78.5 meters.
The most intriguing intercept of the winter program came in TET16210, a hole drilled about 200 meters southeast of the nearest hole at North Peak and 200 meters northeast of the Peak deposit.
This wildcat hole cut two mineralized intercepts, including 43.96 meters averaging 3.28 g/t gold.
Cutting grades and thickness remarkably similar to those identified in both Main Peak and North Peak, this discovery hole in the aptly named Connector zone provided a clear indication that the seemingly separate Peak deposits may link up to form a roughly 2,000-meter arc of contiguous high-grade skarn mineralization. This would be roughly three times the footprint of the Main Peak deposit outlined in 2013.
"The winter drilling program was successful in expanding the known limits of both the Peak and North Peak zones, and perhaps most importantly found new, significant mineralization in its first drill hole in the Connector zone that may lead to a better understanding of the relationship between Peak and North Peak and possible further expansion of the mineral system," said Contango Ore President and CEO Brad Juneau.
Above expanding the breadth of the Peak zones, the initial phase of 2016 Tetlin drilling bolstered the confidence in the geological model for the deposit(s), setting the stage for a 12,601-meter summer drill program that encountered the best intercepts ever, when you consider the long widths of high-grade gold encountered.
Higher peaks
Prophetically, Contango Ore CEO Brad told Mining News at the onset of the summer program, "I think it is starting to get really exciting out there."
This excitement began when the first batch of drill results from the summer program were published in June, with some of the best holes drilled in the area southeast of North Peak, in the direction of the Connector zone.
• TET16211 cut four mineralized intercepts, including 10.31 meters averaging 3.5 g/t gold from a depth of 16.11 meters.
• TET16220 cut three mineralized intercepts, including 26.03 meters averaging 4.67 g/t gold from a depth of 30.2 meters.
• TET16221 cut four mineralized intercepts, including 17.92 meters averaging 8.23 g/t gold from a depth of 21.61 meters.
The excitement continued to build with a mid-August batch of assay results that included the best intercepts ever drilled at Tetlin when you consider the very high gold grades across long lengths.
• TET16235, drilled about 150 meters northwest of the Connector discovery hole, cut three gold-rich intercepts, including 38.88 meters averaging 51.62 g/t (1.66 oz/t) gold from a depth of 14.5 meters.
• TET16237, drilled about 70 meters north of 235, cut five gold intercepts, including 14.19 meters averaging 45.33 g/t (1.43 oz/t) gold from a depth of 9.75 meters.
• TET16227, drilled about 100 meters northeast of 235 cut two gold intercepts, including 10.75 meters averaging 18.62 g/t gold from a depth of 21.56 meters.
"The Connector hole (TET16210) was originally drilled in an attempt to test a geologic model indicating the Main Peak zone may connect to North Peak," explained Juneau. "The new core holes show that gold mineralization is present from the Connector hole to North Peak, and hole TET16235 in this newly delineated area has the highest amount of gold grade (times) thickness drilled to date."
While the impressive gold grades released in August seemed a likely apex to a drill program that had produced increasingly impressive results, another batch of assays released on Oct. 20 summited a higher peak.
• TET16256, drilled roughly 125 meters east of hole 235, cut 13.2 meters of 48.59 g/t (1.56 oz/t) gold from a depth of 7.92 meters.
• TET16269, drilled about 150 northwest of hole 235, cut five zones of mineralization: 17.63 meters of 2.27 g/t gold from 25.3 meters; 8.54 meters of 2 g/t gold from 47.93 meters; 13.9 meters of 13.97 g/t gold from 60.66 meters; 3.02 meters of 8.84 g/t gold from 91.9 meters; and 17.38 meters of 9.7 g/t gold from 108.27 meters.
Adding to the impressive results from North Peak, TET16271 encountered multiple long zones of high-grade gold. Drilled between 235 and 269, this hole cut 17.2 meters of 51.89 g/t (1.67 oz/t) gold from 24.08 meters; 9.19 meters of 41.02 g/t (1.32 oz/t) gold from 44.73 meters; 13.95 meters of 24.28 g/t gold from 57.25 meters; and 3.31 meters of 4.47 g/t gold from 82.32 meters.
The company enjoyed similar success when it dropped back into the Main Peak zone to drill two holes aimed at ensuring the predictability of the skarn geometry, grades and thicknesses of the gold mineralization found there.
The first such hole, TET16267, cut two zones of mineralization, including 50.85 meters of 12.05 g/t gold from a depth of 110.39 meters.
TET16238, drilled roughly 150 meters southeast of hole 267, cut four zones of gold mineralization, including 67.89 meters of 8.39 g/t gold from a depth of 105.39 meters.
"The primary goal of the 2016 phase-2 drilling was to expand the known resource areas and to confirm the continuity of high-grade gold mineralization between previously drilled fences in North Peak resource areas," explained Juneau. "The results exceeded our expectations and established continuity between previously drilled holes at Main Peak and the new infill holes at North Peak."
Following the completion of roughly 16,640 meters of drilling during the first two phases of 2016 exploration, Peak Gold launched a third phase that is expected to run into November.
An updated resource estimate that reflects Peak Gold's two years of increasingly successful drilling in the Connector, Main and North Peak zones is slated for completion around March of next year.
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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