The state Department of Transportation and Public Facilities has released its summary of a reconnaissance study of possible road and rail routes to the Ambler Mining District of the western Brooks Range. The least expensive option, and the quickest to build, appears to be a road from the Dalton Highway to the Ambler district. Other routes for roads, and several options for railroads in the study, were longer and more expensive.

There are three significant known mineral deposits in the Ambler Mining District. The best known is Arctic roughly in the middle of the region, which has high grades of copper. At the eastern end is Sun, which has copper, zinc, and significant showings of silver. Smucker is to the west, a zinc deposit that also appears to have significant silver. Active exploration is underway at Arctic and Sun, but Smucker has been little recent exploration. Companies exploring in the region historically have been Kennecott Minerals, Anaconda and Cominco, and Noranda. More recently NovaGold Resources and NANA Regional Corp. have been active.

A road might not be enough to insure the Ambler development, however. Mining experts tell us that a road to the Dalton Highway would enhance exploration but would not, most likely, lead to development of a producing mine. That’s unless there is a mine with very rich ore that can stand the cost of a long distance truck transport. The distances with the two best road alternatives would be 220 miles to 240 miles (depending on the route) to the junction with the Dalton at Prospect Creek. From Prospect south there is another 220 miles by road to Fairbanks and a connection with the Alaska Railroad.

The Arctic deposit now being explored by NovaGold Resources has a high content of copper, and the Sun and Smucker deposits have significant silver. However, the amount of ore now defined by drilling is not yet sufficient for a mine, and so exploration continues. Bornite, a known copper deposit southwest of Arctic, could contribute to the “critical mass” of mines needed to justify infrastructure.

Mines do transport their concentrate production long distances by truck, of course, and cases of this should be examined. The case most familiar to Alaskans is the transportation of zinc and lead concentrate by truck from the Red Dog Mine, in the De Long Mountains north of Kotzebue, about 60 miles to a port facility on the Chukchi Sea, where the ore is stored there and shipped by sea in the summer. Another example is ore shipped by truck from mines in Yukon Territory via the Klondike Highway to Skagway, from where it is also shipped by sea.

The apparent consensus in the mining community, for now, is that to develop producing mines a railroad is needed in the long run. Rail would be the most efficient way to transport large tonnages of ore concentrates from mines likely to be developed in the region. Still, it is likely to take several large producing mines to justify a railroad.

While the shortest and least costly rail options identified in the DOTPF study all go west from the Ambler region, but all of these cross federal conservation land units and should not be considered as practical options. A rail connection with the existing Alaska Railroad either near Fairbanks or Nenana may be what is needed, although these options are costly. The price tags for two of the most feasible rail route options in the DOTPF study are $1.9 and $2 billion, respectively. An investment in the range of $2.5 billion to do both a road and, subsequently, a railroad, may be a good investment, however. The state Legislature will be cautious in committing very large sums until more ore is found. The more prudent option would be to build the road first to enhance exploration, followed by a railroad when sufficient ore is found and companies are willing to commit to developing mines.

Long history of exploration in the Ambler region

There is a long history of exploration in the Arctic/Bornite region and in other parts of the region as well. Prospectors had long been in the area and the first discovery, at Bornite, was made by a well-known prospector, Riney Berg, in the early 1950s. Berg got further backing from three other well-known Alaskans, Kotzebue air taxi operator Bobby Baker (who is also given credit for bringing the Red Dog zinc deposit to the attention of geologists; Chuck Herbert, who later became a state Commissioner of Natural Resources, and Edith Bullock, a businesswoman in the transportation industry.

The Bornite prospect was sold to Kennecott Minerals Co. in the 1960s. Kennecott invested substantially in exploration and built a deep shaft to approximately the 1,000-foot level to do underground drilling and extract bulk ore samples. However, the shaft flooded soon after it was completed. The company decided not to dewater and rebuild the shaft and instead shifted its focus elsewhere in the region and eventually made the discovery at Arctic, to the northeast. Kennecott eventually sold Bornite to NANA Regional Corp. of Kotzebue, which is the current owner, and after doing more work at Arctic sold 51 percent of the property in 2004 to NovaGold Resources and the remaining 49% share in 2010. NovaGold and NANA are continuing to do exploration work at both Arctic and Bornite. Both had field parties and drilling underway at the two prospects in the 2011 summer season. The two are also discussing merging the ownership of the two properties to enhance their development. NovaGold itself now owns a 45-mile belt of prospects in the area including Arctic.

The Arctic deposit itself contains an “indicated” resource (estimated with closely-spaced drill holes) of 16.8 million metric tons of ore containing copper, zinc, gold, silver and lead. The estimate includes an additional “inferred” (estimated with more widely-space drill holes) resource of 11.9 million tons. In 2010 NovaGold focused on conducting environmental baseline, engineering and metallurgical studies needed complete a prefeasibility study to assess the economics of a mine. The company also evaluated the possibility of establishing some 10 miles of road that would link the property to the Bornite area, where a camp and a 5,000-foot airstrip is established. As part of this study, the company conducted geotechnical drilling in and around the ore body and along the proposed route of the road. In 2011 the company resumed drilling and began work on a prefeasibility study.

Sun/Picnic Creek

At the Sun prospect to the east Andover Ventures did new drilling in 2011 on its 17,980 acre holding, with silver, copper, zinc, lead and gold. Previously, the company had drilled in 2007. Anaconda Copper Mining Company, Cominco Inc., and Noranda Inc. explored Sun and Picnic Creek, an adjacent prospect, during the 1970s and 1980s. A resource calculated for Anaconda in 1977 estimated the Sun project with a resource of 17.9 million tons of ore resources that would have to tapped by underground mining, with an additional 2.4 million tons of ore that could be produced with lower-cost open-pit mining.  Andover drilled 20 holes in 2007 to confirm results from the earlier drilling and drilled another six drill holes in 2011. In total there have been 50 test holes drilled at Sun by all companies. Andover has now commissioned an independent resource evaluation of the prospect.

Smucker

There isn’t a lot in the public record about Smucker. Teck Alaska, which operates the Red Dog Mine, holds the core mining claims at Smucker, which are unpatented. There are reports that another company has staked ground around the core claims. What is available publically is that there were eight drill holes drilled in 1984. Two of the drill samples, done 2,400 feet apart, showed high values for silver with additional values for zinc and lead. Another report, in 1986, estimated greater than 8 million metric tons of ore resources with copper, zinc, lead, and silver. One other report in 1996 reported “significant” tonnage of ore.