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keywords:( cold)
Tractors speed placer development in Alaska
Saga of comstock lode, boom days in Virginia City
Possibilities of the Mother Lode in depth
Mining of Mercedes orebody, Macuchi, Ecuador, South America
Lodes in the tertiary eruptions of Colorado
Big wonder syndicate's Auriferous lodes
Air-transportation of gold dredges in new Guinea
Air-transportation of gold dredges in new Guinea
Air-transportation of gold dredges in new Guinea
Air-transportation of gold dredges in new Guinea