Wednesday, October 17, 2012

Samppi Mine near Chatanika typical of old drift mines that dot Interior Alaska

The giant dredges scattered along the creeks around Fairbanks are testament to the decades when dredging dominated local gold production, just as the headframes and mill buildings in the hills are reminders of hard-rock mining.

However, there are few reminders of the drift mines that initially supported Fairbanks and the mining camps surrounding it. The major reason so few of these operations still exist is because the dredges reworked much of the creek bottoms, tearing up any evidence of previous mining activity.

The drawing is of the above ground portion of the Samppi drift mine on Ruby Creek, about two miles south of Chatanika near the old Tanana Valley Railroad right-of-way. Dredges never made it to this area.

Placer miners in the Fairbanks area had to deal with the thick layers of frozen “muck” that covered the gold-bearing gravels. Miners burrowed down to those gravels, and then followed the “paystreak” by digging horizontal tunnels called drifts.

According to the book, Historic Resources in the Fairbanks North Star Borough, the initial step was sinking vertical exploratory shafts. (Where I grew up in California, these were called “coyote holes.”) Frozen ground was first thawed with a fire or hot rocks (later with steam points), and the thawed soil excavated. This process was repeated until bedrock was reached. If miners were lucky, they found gold in sufficient quantity to mine. If not, they started over again elsewhere.

If gold was discovered the miners drifted along the paystreak, thawing the ground, excavating the gold-bearing gravel and hauling it to the surface. All this had to be done while the above-ground air temperature was below freezing. Miners foolish enough to excavate in frozen ground during warm weather ran the risk of collapsed tunnels.

The simplest drift mines used hand-cranked windlasses to lift gravel to the surface. Larger operations like the Samppi mine used steam-operated winches and a “gin pole” system. A gin pole is a pole standing to the side of a shaft. (In the case of the Samppi Mine, it was two poles lashed together.) The pole is held in position with guy wires.

Most operations also used three additional cables: a “high line” fastened to the top of the pole on which a “carrier” rode to move the ore bucket; a hoist cable to lift the bucket out of the shaft and pull the carrier up to the gin pole, and a trip cable. The chain on the front of the ore bucket was looped over the trip cable, and would automatically dump the bucket when the carrier reached the winter dump site. In this way gold-bearing gravel was stockpiled until summer when it could be sluiced out. (For more information on drift mining and other gold recovery techniques used by Alaska miners click here.)

The Sampii Mine was operated by Melvin Samppi. I couldn't find any mention of the mine in old issues of the "Fairbanks Daily News-Miner," but there are ample references to Melvin and his wife, Devina, who were active in Fairbanks during the 1930s and 40s.

The last time I visited the mine there were still three buildings standing: a bunkhouse, the boiler and hoist shack, and an outhouse. (Actually, the boiler house was barely standing — the boiler’s stack had collapsed onto the roof, and there was asbestos insulation everywhere.) The gin pole was still standing and the ore bucket (with attached carrier) was sitting in the trees. Ruby Creek runs between the gin pole and the mine shaft, and just upstream was a containment dam to stockpile water for sluicing.

If you do go out tramping in the hills, always check land ownership before you go. I crossed private property to get to Ruby Creek, but had permission from the property owner. Also, in most mining areas there is always the danger of abandoned shafts, often concealed by vegetation. Look before you leap.

      Historic Resources in the Fairbanks North Star Borough, Janet Matheson & F. Bruce 
          Haldeman, 1981 
       Alaska Mining History and Techniques, National Park Service, no date
      Placer Deposits of Alaska, Edward H. Cobb, 1973, Geological Survey Bulletin 137 
       Tanana Valley Railroad, the Gold Dust Line, Nicholas Deely, 1996

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