Gold rush era (1896-1899)

During the gold rush some gold was found in the creek beds, but most was in the valley gravels near and in the bedrock. The recovery had two steps: bringing the gravel containing gold to the surface and then separating the gold from the gravel using water and gravity separation. As a result, access to water was important since it was necessary for the separation process and could also be used to thaw the permanently frozen ground and to wash down gravels from the upper terraces.

Methods of bringing out the gold

The first step of recovery was to bring the mixture of gold and dirt from the ground to the surface or from a hillside down to a bench. There were two methods: digging a shaft or using pressurized water to either wash soil down a hillside or suck it up from the ground.

Underground mining

Most of the gold was below the surface. The miners first had to thaw the

permafrost Permafrost is ground that continuously remains below 0 °C (32 °F) for two or more years, located on land or under the ocean. Most common in the Northern Hemisphere, around 15% of the Northern Hemisphere or 11% of the global surface ...

before they could dig. A fire burning all night was used to soften the ground. This would then thaw to a depth of about 14 inches and the gravel could be removed. The process was repeated until the gold was reached. No support of the shaft was necessary because of the permafrost. However, the fire could produce noxious gas which had to be removed. Over time steam for thawing the ground was also taken into use. Normally digging was done during the winter. The cold air would sink down into the shaft and renew the air automatically. At the same time, the temperature meant that shafts, apart from not needing support, were not at risk of being filled with water. A dump was made that could be sluiced during the summer. In the dump, the gold was protected from theft because it was invisible in frozen gravel.Information Sharing During the Klondike Gold Rush. p. 11-12
/ref> Miningsteam.jpg, Principles of mining with steam Thawing-eldorado-creek-1898.jpg, Thawing ground with steam, 1898 Miningshafttech.jpg, Principles of mining with shaft Shaft-pile.jpg, Steam plant, sluice and dump, Hunker, ca. 1901

Hydraulic methods and mining in benches

Jets were applied to wash down part of a hillside for sluicing.GeoWeb
/ref> The stream could be so strong that it would reflect a crowbar swung at it. When gravity could not be used for sluicing, a lift could be applied; it used pressurized water, introduced at the bottom, to suck up a mixture of water and gravel.
/ref> This could also be an alternative to shaft mining as seen on picture 2. Hydraulic methods were introduced during the

California gold rush The California Gold Rush (1848–1855) was a gold rush that began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California fro ...

and would be used later at Nome. Hydraulicbonanza1899.jpg, Jet of water washing down a hillside, 1898 Bench-mining-98.jpg, Mining with sluices on hillside at Klondike, 1898 Skookum-jim-bonanza-1898.jpg, Hydraulic lift on discovery claim, 1898

Separation methods

All methods required water and because of that they could only be used during the summer. Panning for gold was the simplest method of recovering gold, but mostly used for prospecting since it was slow. A faster way was by a rocker box or by sluicing. Dirt was filled into the box or sluice together with water and rocking movements or gravity would make the gold particle go to the bottom whereas sand and fine gold particles would flow off with the water. Further purification of the gold could be done with mercury that would amalgamate with gold only and leave fine sand particles out. A magnet could be used to separate fine magnetic sand from gold dust. Panning2.jpg, Panning for gold, 1898 Rocker.jpg, Rocker box, 1898 Klondike mining camp.jpg, Sluices, Bonanza Creek, 1899

Later operations (1910-1950)

Dredges Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing da ...

were used in the Klondike River valley from 1910-1950.Quest Connect, dredges
/ref> A dredge could do the work of 2,400 persons while operated by 10-12.
/ref> It would create a pool of water that moved along with it as it dug up gravel in front and deposited it behind itself. Inside sand and gold particles were separated from rocks and then gold from sand. By sweeping from side to side around a pole it could cover an area wider than itself.National Park Service, Mining History and Technique
/ref> Today a mixture of hydraulic methods together with bulldozers are used.v

/ref> Image:Dredge-klondike-1913.jpg, Dredge at Bear Creek, 1913 Image:Dredge-piles.jpg, Sandbars made by dredge, Klondike, 1913

References

{{Reflist, 3 Klondike Gold Rush