The Nature of Klondike Gold

There was innovation as well as disruption in the Yukon in the late 1880s, for it was in this period that the techniques of mining in permafrost were developed. Joe Ladue had experimented with these at Fort Reliance during the winter of 1882-83, and they were perfected five years later during the rush to the Fortymile district.

The gold that lay beneath the ground in the Yukon Valley was locked in the soil for all or part of the year by permafrost. Near the surface the ground thawed in the summer, releasing the gold, but farther down the dirt and the gold within it were permanently frozen. If the miners were to work their claims for more than a few months each year, they would have to find a way to free from the frozen soil the flakes and small nuggets that made up the placer gold. In the early days the technique employed was called "skim digging." This involved working during the summer on the top two feet or so — about a metre — of the surface gravel along the creek beds. Below this depth either water was encountered, which made the work impossible, or permafrost, which made it too difficult to be profitable.

When coarse gold was discovered in the Fortymile district, however, the miners began to look for ways to mine the soil down to bedrock. They assumed that because gold was heavy, the greatest concentrations would be found in the gravels that lay just above the bedrock. This was not always the case, as the history of the Klondike discoveries later showed, but there was a bigger problem — how to deal with the permafrost?

In 1887-88, when William Ogilvie of the Geological Survey of Canada was wintering near Fortymile, he suggested to the miners a technique he had seen used in Ottawa to reach broken water mains during the winter. Fires, he said, should be built to thaw the soil, which would be scraped off; then a new fire should be built, and so on to bedrock. The thawed soil could be piled beside the shaft until spring freed the creek water which was necessary to wash the gold from the dirt. This suggestion was immediately adopted (some miners, like Joe Ladue, had already experimented with it), and it became the pattern for the early stage of mining in the district. Thus, most of the actual mining — the digging — took place in the winter. An advantage of this technique was that no timbering was necessary in the mining shafts, which often ran horizontally as well as vertically under the ground. The permafrost was as hard as granite and would not collapse, unless weakened by fire or an early thaw.

The payoff occurred after the spring thaw, when the gold, if there was any, was washed from the dirt. This was originally done with a shallow metal pan which looked like a cross between a pie tin and a washbasin or a Chinese wok, with a smallish flat bottom and gradually sloping sides. Dirt and water were put in the pan, then the pan was moved in a circular manner so that the water and some of the dirt swished around the pan and then slopped over the side. The water, being lightest, would run over the side first, then the lighter soil, then the sand and gravel; the gold flakes and dust, being much heavier, stayed at the bottom. After this had been done several times, nothing was left but whatever gold the dirt had contained. Tourists in the Yukon are still invited to try their hands at this simple technique.

Panning was simple and cheap, but not very efficient; inevitably, a certain amount of gold escaped with the water and dirt. It was also time-consuming, and thus came to be used mostly for initial testing of the value of paydirt, or on claims where the dirt was so rich that some loss did not matter. More efficient was the rocker box, which looked like a turn-of-the-century washing machine and separated the gold from the dirt by vigorous agitation.

The third method used in the Fortymile district and later in the Klondike was the sluice box. This was a wooden trough, typically 6 to 10 feet (1.8 to 3 m) long, with little wooden crosspieces about half an inch (1.3 cm) in height, called "riffles," nailed at intervals to the bottom. The sluice box was fixed at an incline, and water was run in at the higher end. When gold-bearing dirt was shovelled in with the water, the water washed the dirt out the lower end, while the heavier gold sank to the bottom and was caught by the riffles. Every so often the water was diverted from the box, and the gold scraped from the riffles. Sluice boxes were much more efficient than pans or rockers, but they needed a good supply of water — easy enough to come by in the early days, but more difficult later in the Klondike when hundreds of miners were competing for the flow of one small creek.

There was an alternative method that used much less labour, and winter mining to be avoided altogether. This was hydraulic mining, which was developed in California and reached the Yukon Valley in 1890. It involved directing high-pressure hoses at the banks and beds of creeks. Because the creeks were made up of loose aggregate of rocks, soil, and gravel, the material was easily broken up by these hoses, and the resulting slurry was directed into sluice boxes. The pressure was created by flumes from neighbouring creeks directed downhill in the manner of a small hydro-electric plant. The first one on the Fortymile, built by Frank Buteau, George Matlock, and their partners, developed 24 feet of pressure, and ate the ground away in giant bites. This technique was developed further in the Klondike.

Source: K.S. Coates and W.R. Morrison, Land of the Midnight Sun: A History of the Yukon (Montreal: McGill-Queen's University Press, 2005), 56-7

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