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Section of a drift mine in frozen gravel
 

 

 

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Description
English: Diagram illustrating drift mining in permafrost as practiced in Alaska and Yukon in the early 20th century. The deposit is usually an old stream bed overlain by gravel. The greatest concentration of gold is near the bedrock. The gravel is thawed with steam points driven into the mass. The thawed mass is dug out, keeping the gold-bearing material separate from the overburden The gold-bearing material is sent for washing while the overburden accumulates as a pile in the tunnel.
Date copyright 1909
Source Through the Yukon and Alaska [1] Mining and Scientific Press, San Francisco, 1909 p215.
Author T.A. Rickard
Permission
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This media file is in the public domain in the United States. This applies to U.S. works where the copyright has expired, often because its first publication occurred prior to January 1, 1923. See this page for further explanation.
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