Gold is where you find it! Whether taken literally or metaphorically, this old adage is guiding a throng of modern fortune hunters to Alaska. Today, the Far North state has four hardrock mines churning out some 800,000 ounces of gold per year and with three enormous projects set to begin seeking operating permits this output could easily top 3 million ounces annually.
“I think it is significant that Alaska is the No. 2 gold producer in the United States. It is right behind Nevada and gaining ground. When you get projects like Donlin Gold into production it will start rivaling Nevada,” said NovaCopper President and CEO Rick Van Nieuwenhuyse.
Over the past 25 years, explorers have outlined Pebble, Donlin Gold and Livengood — enormous accumulations of gold that are measured in the tens of millions of ounces. Though globally significant, these projects only begin to account for some 25 million ounces of placer gold recovered from the vast and underexplored expanse of Alaska.
“I think there is tremendous exploration opportunity in all of the alluvial districts that Alaska has. There are probably 50 districts in Alaska that have produced more than a quarter-million ounces of gold,” said Van Nieuwenhuyse.
With only the oil-rich plains of the North Slope lacking an aurum discovery, Alaska is truly the Last Frontier for hunting mammoth gold deposits in the United States.
TGB East
The Tintina Gold Belt is a popular destination in North American for fortune hunters seeking the next multimillion-ounce gold deposit in Alaska. World-class deposits at Fort Knox, Pogo, Donlin and Livengood only begin to account for the hardrock source of more than 17 million ounces of alluvial gold recovered from the vast aurum province that sweeps some 850 miles across the breadth of the state.
Alaska’s portion of the Tintina Gold Belt can be divided into two distinct groups — the eastern extent, which runs from the Alaska-Yukon Territory border some 300 miles into the state, and the 74,000-square-mile Kuskokwim Mineral Belt in southwestern Alaska.
The eastern half of Alaska’s Golden Arch is home to the state’s two biggest gold operations — Kinross Gold Corp.’s Fort Knox Mine and Sumitomo Metal Mining’s high-grade, underground mine at Pogo.
Though in terms of size, International Tower Hill Mines’ Money Knob gold deposit at Livengood substantially outweighs its Interior Alaska neighbors. Similar in grade to Fort Knox about 70 miles to the southeast, Money Knob is the first significant lode discovery in Tolovana, a district that has produced some 600,000 ounces of placer gold.
Since 2006, Tower Hill has expanded Money Knob from an obscure prospect to a world-class ore-body encompassing 20 million ounces of gold.
The significance to contemporary gold explorers is that this recent top-tier gold discovery sits adjacent to, and potentially under, the Elliot Highway — demonstrating that even easily assessable regions of Alaska are woefully underexplored.
“I think Livengood underscores the lack of exploration that has been done in the region. Each one of these major placer gold districts — and there are quite a few of them — have a lode source and by-and-large these have not been explored for in any great detail,” said Van Nieuwenhuyse.
The Circle Mining District, situated about 100 miles east of Livengood, and the Fortymile Mining District adjacent to the Yukon Territory border are two such promising areas.
Circle and the other mining districts in the eastern extent of the Tintina Gold Belt share a common geologic and glacial history to the celebrated White Gold and Klondike districts in neighboring Yukon.
This parallel begins to explain why the lode source of the placers remains hidden and hints at the techniques that could discover the hidden gold.
“There are a lot of these alluvial districts out there where gold has accumulated through weathering processes over the years but there is no outcrop,” explains Van Nieuwenhuyse.
Full Metal Minerals Ltd. — which shared its managers and geologists with Underworld Resources Inc. during that junior’s exploration of the renowned White Gold deposit in the Yukon — is applying similar exploration techniques in Alaska.
Recognizing the belt of Cretaceous-age deposits, prospects, and placer gold mines of Yukon’s White Gold district trends into Alaska, Full Metal geologists surmised that similar mineralization might be the undiscovered lode of more than half a million ounces of placer gold recovered from streams draining the rolling hills of the Fortymile district some 60 miles to the northwest.
Using placer gold-producing streams to vector their search, Full Metal geologists have traversed the hilltops and ridges of the junior’s Rolling Thunder claims in the Fortymile. This reconnaissance sampling and mapping has identified multiple areas of strong alteration and quartz veining reminiscent of White Gold.
Full Metal is applying the same system to seek the hidden lode of some 1 million ounces of placer gold recovered from the streams of the Circle district. Like the Fortymile, Klondike and White Gold districts to the east, bedrock exposure in the Circle region is very limited, with soil sampling the most effective reconnaissance tool in this unglaciated terrane.
Though legendary placer mining districts are compelling targets, fortune hunters should not limit their search to these areas. The Goodpaster Mining District, for example, has only produced about 2,000 ounces of alluvial aurum, yet it is home to Pogo, Alaska’s most prolific gold mine.
With ore that averages about 14 grams per metric ton, the 2,500-metric-ton-per-day underground operation at Pogo churns out some 380,000 ounces of gold per year.
Geologists believe that Pogo is only the first economical gold deposit that will be discovered in this region between the Fairbanks and Fortymile districts.
“I honestly believe that there will be other ore-bodies found in that area — it very underexplored so far,” said Millrock President and CEO Greg Beischer. “There is going to be more mines in that region.”
The eastern half of the Golden Arch is also known to host gold-enriched volcanogenic massive sulfide deposits and is highly prospective for porphyry gold-copper deposits.
Heatherdale Resources Ltd. is exploring precious metals-enriched VMS mineralization at its Delta project, located in the southern margins of the Tintina Gold Belt about 36 miles southwest of the town of Tok.
An inferred resource of 15.4 million metric tons grading 0.6 percent copper, 1.7 percent lead, 3.8 percent zinc, 62 g/t silver, and 1.7 g/t gold has been calculated for Delta. Explorers also found large massive sulfide boulders on the 39,840-acre (16,123 hectares) property that average 113 g/t silver, 7.3 percent lead, 5.6 percent zinc, 113 g/t silver and 0.7 g/t gold.
“Delta is an early-stage project, but it also represents an emerging massive sulfide district with the potential to be in the top tier of global districts of its type,” Heatherdale President and CEO Patrick Smith said of the find.
Hints of porphyry gold-copper mineralization have been found in the Fortymile district and near Livengood in the Tolovana district.
Kuskokwim Mineral Belt
The geology of the Tintina Gold Belt begins to change as it continues westward from Livengood and begins to arc southwest. This sub-region — referred to as the Kuskokwim Mineral Belt — has produced some 4 million ounces of gold, 500,000 ounces of silver and more than 40 million ounces of mercury.
The 40-million-ounce Donlin Gold project — being developed by Barrick Gold Corp. and NovaGold Resources Inc. — is the crown jewel of the Kuskokwim. Over the past several years, majors and junior explorers alike have scoured this region in search of other large intrusive-related gold deposits, uncovering several promising prospects.
“There are a lot of porphyries throughout that belt that are a similar age to Donlin so I think there is tremendous opportunity there,” said Van Nieuwenhuyse.
McGrath, a century-old gold mining town, serves as a hub for companies seeking Donlin-style porphyritic intrusive rock in the upper reaches of the Kuskokwim Mineral Belt.
Ganes Creek — which is famed for its enormous gold nuggets, including the 5th- and 13th-largest ever found in Alaska, at 122 and 62.5 troy ounces, respectively — is an alluvial stream about 25 miles west of McGrath that is reminiscent of Donlin.
This legendary stream has given up some 250,000 ounces of placer gold and an estimated 734,000 ounces of the alluvial aurum still remains. The coarse nature of the gold suggests that the lode is lurking in the nearby uplands.
Vinasale — found about 16 miles south of McGrath — is another intrusive-related gold project that demonstrates the promise of this gold-rich region. Freegold Ventures Ltd. — the junior exploring Vinasale — is expanding on some 1.33 million ounces of gold outlined here to date.
To the northeast of McGrath lies Ruby-Poorman — another Alaska mining district that has produced 500,000 ounces of gold with a yet-to-be discovered hardrock source.
“Ruby-Poorman is a 30- to 40-mile-long alluvial district that has produced a substantial amount of gold, yet there is not rock-one you can look at,” explained longtime Alaska explorer Van Nieuwenhuyse. “We have got to build up that database of detailed geophysical surveys and get in on the ground and do some baseline auger-type sampling to see what’s down there.”
Besides Donlin Creek-style mineralization, the Kuskokwim belt also hosts Nixon Fork, a carbonate skarn deposit rich in copper, silver and high-grade gold. Mercury, antimony, tin, platinum, tungsten, rare earth elements, and native bismuth have been recovered with the placer gold found here.
Porphyry-rich SW Alaska
Paralleling the Tintina Belt to the south lie a band of mineral-rich terranes, or related rock formations, drawing the attention of senior and junior miners. This arc consists of the Wrangellia Composite and Kahiltna terranes, two interrelated but distinct assemblages.
The Kahiltna Terrane — home of the enormous Pebble deposit — is highly regarded for its potential to host other world-class porphyry copper-gold and intrusive gold deposits.
With its 80.6 billion pounds of copper, 107.4 million ounces of gold and 5.6 billion pounds of molybdenum, the Pebble deposit ranks amongst the world’s largest for any of these metals — combined it is extraordinary.
Formed when the Wrangellia Composite Terrane thrust up the ocean floor as it collided with Alaska and pumped with copper and gold-bearing fluids at least twice, the more than 400-mile-long Kahiltna Terrane provides the ideal setting for explorers to search.
“The discovery potential is very high for porphyry deposits generally in this arc environment, but I would also say that Pebble-look-alikes are probably not likely. However, this does not preclude the potential to find other large porphyry deposits with their own unique sets of characteristics. So, we should not over-focus on the Pebble model, but we should focus more on the favorable environment that Pebble represents,” Pebble Partnership Chief Geologist Jim Lang observed.
Though the Kahiltna assemblage is best known for its porphyry and other intrusive-related copper and gold projects, the region also is highly prospective for other styles of mineralization.
“All over the Kahiltna Terrane keep your mind open to any style of mineralization — it could be VMS, a skarn or a great big vein,” Beischer said.
Southwest of Pebble, the Alaska Peninsula and Aleutian Island stretches some 1,000 miles out into the Pacific Ocean.
“I think the other area that is kind of forgotten is the Alaska Peninsula. You have Pebble out there, one of the largest metal accumulations on the planet. The rest of the peninsula ranks high in potential,” said Van Nieuwenhuyse.
This island arc, formed as the Pacific Ocean plate dives under the North American plate, has received limited modern exploration and is prospective for both epithermal gold, and porphyry copper-gold mineralizing systems.
The Pyramid copper-molybdenum porphyry and the nearby Unga-Popov epithermal gold projects highlight the potential of the region.
Pyramid — which hosts 125 million metric tons of near-surface mineralization grading 0.403 percent copper and 0.025 percent molybdenum — is being drilled by Full Metal and Chile-based project partner Antofagasta Minerals S.A.
Unga-Popov — an epithermal gold project on an island about 25 miles (40 kilometer) south of Pyramid — hosts two historical resources; Apollo with 280,000 metric tons averaging 27.7 g/t gold and 92.6 g/t silver and Centennial, which has about 6 million metric tons at 1.5 g/t.
Legendary Seward Peninsula
From the 1898 gold strike made by the “Three Lucky Swedes” a few miles from Nome, to the Discovery Channel’s reality series, “Bering Sea Gold”, the Seward Peninsula is legendary.
Though this 20,600-square-mile isthmus in Northwest Alaska is one of the world’s most prolific placer-producing regions, only about 30,000 ounces of lode gold has been mined there.
The rivers and beaches of the Nome Mining District itself produced more than half of the placer gold that lured tens of thousands of fortune hunters to this far western region of Alaska at the turn of the 20th Century.
“The (Nome) district has produced some 5 million ounces of alluvial gold. We certainly see the potential for additional targets there,” Van Nieuwenhuyse said.
Rock Creek, which NovaGold put on care and maintenance before reaching commercial production, is the only modern hardrock mine on the peninsula. Bering Straits Corp., the area’s Alaska Native regional corporation, recently agreed to acquire the defunct operation and plans to put it into operation.
Exploring two Seward Peninsula gold properties, Millrock Resources is among the most tenacious of the contemporary explorers in the region. This junior, in partnership with Kinross, is gearing up to drill Council, a 900-square-mile land package that blankets a region that has produced some 500,000 ounces of placer gold.
NANA Regional Native Corp. — Bering Straits Corp.’s traditional neighbors to the north — is seeking the lode source of some 580,000 ounces of alluvial aurum recovered from the Fairhaven Mining District on the north coast of the Seward Peninsula.
Exploration by NANA has outlined an orogenic-stratabound gold system adjacent to the Kugruk Fault. Geologists have picked up rock samples assaying up to 9.4 g/t and 7.6 g/t silver at Motherwood Point, where this fault zone meets the northern shore of the Seward Peninsula.
“There is very little outcrop on the northern part of the Seward Peninsula — those districts have produced a fair bit of gold, and there is known copper and zinc occurrences all through that country,” said Van Nieuwenhuyse.
Due to the lack of outcrop, NANA geologists are using geochemical surveys to refine their search of this gold-rich region located at the southern margin of their traditional territory.
Big Arctic nuggets
The Brooks Range — a chain of mountains that spans the more than 600-mile-width of Alaska north of the Arctic Circle — marks the northern extent of known gold mineralization in Alaska.
Chandalar and Koyukuk-Nolan districts along the southern slopes of the central portion of this mountain chain are particularly rich placer-gold regions. High-grade orogenic veins are the suspected source of the large gold nuggets found in these placer districts located above the Arctic Circle about 200 miles north of Fairbanks.
“Those are very rich gold deposits so I am a bit surprised that there hasn’t been more work there,” Van Nieuwenhuyse commented on these Brooks Range gold districts.
An estimated 84,000 ounces of gold has been recovered from the Chandalar district. About 76,000 ounces of the yellow metal, or about 90 percent of the total, was alluvial gold found in the stream beds and frozen bench gravels. Most of the remaining 10 percent of the total was recovered from the Mikado Lode.
Goldrich Mining Co., a junior mining company that holds claims over most of the Chandalar district, said Mikado is one of about 30 auriferous quartz-sulfide veins that are now documented on the property. Very little modern exploration work has been completed at Chandalar.
The Koyukuk-Nolan district, which lies directly west of Chandalar, has produced about 350,000 ounces of placer gold. The region is well-known for producing large nuggets. The third (146 troy ounces), fourth (137 troy ounces), 14th (61 troy ounces) and 17th (55 troy ounces) largest gold nuggets ever found in Alaska were mined on the Hammond River, a tributary to the Koyukuk River.
A lode source for these big nugget producing placers is yet to be discovered.
Juneau Gold Belt
Alaska’s gold potential was recognized in 1880 when Auk Chief Kowee, a Tlingit from Admiralty Island, led prospectors Joe Juneau and Richard Harris to the headwaters of the appropriately named Gold Creek.
A year after the find credited to Juneau and Harris, operations began at the Treadwell gold mine situated southeast of Juneau. At its peak, Treadwell employed 2,000 Juneau residents and was the largest gold mine in the world. From 1881 to 1922, more than 3 million troy ounces of gold were extracted from the mine.
The Treadwell Mine lies in the 100-mile-long Juneau Gold Belt, an orogenic gold district that has produced more than 7 million ounces of gold. Today, Coeur d’Alene Mine Corp.’s Kensington Mine about 45 miles north of Juneau is the only current gold operation in Southeast Alaska.
Herbert Glacier, located midway between Treadwell and Kensington, demonstrates the prospectivity of this belt. One hole drilled by Grande Portage Resources Ltd. in 2011 cut 15.3 meters averaging nearly 1.1 ounces per metric ton gold. An initial resource estimate outlines a deposit of 1.57 million metric tons averaging 4.86 g/t gold.
A 450-mile long belt of late-Triassic volcanogenic massive sulfide deposits stretches along the entire length of the Southeast Alaska panhandle encompasses such metals-rich deposits as Niblack, Greens Creek, Palmer and, as the belt continues into British Columbia, Windy Craggy.
Explorers are also finding high-grade orogenic gold in Southcentral, a region noted for historical high-grade gold mines. The historical Independence and Lucky Shot gold mines in Southcentral are just a few examples of historical high-grade gold regions that hold promise for the contemporary fortune hunter.
Tomes can be, and have been, written about Alaska’s gold potential, and more chapters are sure to be added as fortune hunters continue to make new discoveries in this vast aurum-producing state.
