Story last updated at 9/26/2012 - 2:37 pm
Asbestos is a "dirty" word these days because of its health hazards, especially to lungs. Many of us forget that asbestos occurs naturally and is found in Alaska. An asbestos prospect is near the north end of Admiralty Island, about a mile and a half inland. Unfortunately for the locators and developers, the asbestos strands were not of commercial value.
The outcropping was first staked in 1928 by Augustus Nicolas DeRoux of Juneau. It crops out on the west side of a steep cut-bank of a tributary to Bear Creek. The creek flows east four miles to Gastineau Channel. The men accessed the prospect at the 200-foot elevation by a trail from a small cove at the mouth of Bear Creek. On a Juneau Parks and Recreation website, Kenneth DeRoux tells us that Augustus participated in the Klondike Gold Rush, and then in 1899 he opened an assay lab in Skagway. After the Gold Rush, he moved South and returned in 1928 to Douglas. It must have been about this time that he went prospecting on Admiralty Island because he located his claims that year.
In the next couple years, DeRoux and hired men dug an open-cut across the best part of the outcropping. This was a trench along the deposit to expose it. This work later caused the bank to slip so the asbestos became poorly exposed for further exploration. The men constructed a trail to the beach. One source tells us that it was a road. By 1944 several cabins stood on the banks of the tributary. A rail tram was started from the cove, and it stopped after a short distance, never completed.
So why the excitement over asbestos? Asbestos is a name for six different silicate minerals that resist heat, so it is fireproof. It is a good insulation, is strong and flexible, and does not conduct electricity. Most asbestos at that time was spun into a cloth so the fibers needed to be long. The most familiar uses that we know, before health hazards surfaced, were for roofing and siding shingles, interior insulation, textured paint and patching compound. Some of us mature folks remember our mothers had stove top pads. What about those grey-colored sheets tacked around the old wood stoves to prevent fires? The old, basement coal furnace in my grandparent's house had asbestos wrapped around parts of the huge iron machine, it and covered the hot water pipes.
An interesting thing I found researching for this article is that ancient Greeks and Romans used asbestos as napkins and tablecloths. To clean them, the dirty "linen" was thrown into a hot fire. The napkins and tablecloth came out whiter than when put in the fire.
So asbestos has been around for a long time. It was known in prehistoric times in Alaska and found in excavations in ancient villages on the Kobuk River (300 miles from today's Nome). Even the ancient Greeks knew it caused "darkness of the lungs." Over the centuries, this problem was forgotten or ignored.
But, back to the time of DeRoux and Bear Creek. Soon after discovery, the U.S. Geological Survey examined the prospect. By 1930, DeRoux was listed as general manager and half owner of the Shiedly-Roux prospect that operated under the name Alaska Asbestos Company. Ken DeRoux states that Augustus spent much effort to interest investors in the claims. I would guess Shiedly received his ownership for a monetary contribution to advance development work.
DeRoux told a reporter in 1931 that he believed his claim was the only commercially viable quarry in Alaska. At that time the values ranged from $40 for the poorer grades to the finest quality at $350 per ton. This must mean DeRoux or the USGS sent out samples for assay. More than $75 had been invested in the development, and the owners planned to operate on a larger scale in 1931.
The Bear Creek occurrence is thermolite asbestos. The best quality asbestos comes from two of the other six minerals, but thermolite is still commercially viable today. The Bear Creek asbestos occurs in leaves and sheaves of parallel fibers, some 18 inches long, but the weathered, exposed surfaces break across the fibers in small pieces and chunks. By 1944, the asbestos was exposed for a length of fourteen feet, and in places the band was a foot and a half wide. The vertical layer was traced for 60 feet on the surface. The cross-fiber samples (as opposed to parallel fibers) were three-quarters of an inch to six or eight inches long.
In a USGS report, criteria were explained on how to open such a mine: one had to see if better quality asbestos was under the weathered material. The owner also needed to know if sufficient quantity was available before talking to manufacturers. Usually asbestos is mined by the company that processes it. Some asbestos may be usable by one company and not by another.
Again, the USGS collected and tested samples and told DeRoux that the asbestos did not meet the specifications for commercial use. Apparently DeRoux was discouraged by this report and did no further work on the unpatented claims. The last time geologists examined the prospect was in 2005-2006 when the Bureau of Land Management investigated the claims for the U.S. Forest Service. The file is marked "probably abandoned."
The biggest Alaskan asbestos deposits are in the Kobuk River area where the prehistoric people first used it. It wasn't until the Gold Rush that prospectors seriously looked at the Dahl Creek deposits. Several outfits examined the area, but it was not until 1943 before the Arctic Circle Exploration Co. mined 33 tons of tremolite asbestos near the summit of Asbestos Mountain. A 229-foot adit and several trenches were explored and then mined. No further activity at the mine is reported, probably because, like the Bear Creek prospect, the fibers were short and not particularly strong.
Today 36,000 tons of thermolite are mined annually in India.
Pat Roppel is the author of numerous books about mining, fishing, and man's use of the land. She lives in Wrangell. She may be reached at email@example.com.