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In mining in this district many changes were neces- 

 sarily introduced in adapting to the frozen gravels of Yukon 

 the placer mining methods previously understood and 

 employed in California and other temperate climates. The 

 dredges had to be strongly built in order to withstand the 

 severe service of digging the broken schists which compose 

 the bedrock, and the frozen gravel which is almost as 

 impenetrable as granite. Probably the most serious prob- 

 lem, however, was to overcome the frozen condition so that 

 the material could be handled as readily as similar ground 

 in California or elsewhere. These matters are of intense 

 interest to the mining engineer. 



The Yukon Gold Company. — The Yukon Gold 

 Company owns practically all the more important gravels 

 on Bonanza, Eldorado and Hunker creeks and their tribu- 

 taries, the holdings of the company being mainly included 

 in an area about 25 miles (40 km.) in diameter. 



The operations of the Yukon Gold Company in 

 Klondike district are, in general, limited to two phases of 

 placer mining, viz., dredging and hydraulicking. The 

 gravels in the valley bottoms are all dredged, but those 

 higher up on the hills and sidehills, which cannot be 

 conveniently reached by the dredges, are hydraulicked, 

 and in general the lower deposits are first worked so as 

 to afford tailings ground when working the higher gravels. 

 During the season of 1912 an average of about 600 men 

 were employed by this company, 400 of whom were 

 engaged in connection with dredging, about 130 on the 

 hydraulic properties and ditches supplying these with 

 water, and the rest were employed mainly in the machine 

 shops, power plant and stables. 



The Yukon Gold Company has built and is operating 

 eight dredges, as follows: — 



Three Bucyrus 5-foot boats, 

 One Marion 7-foot boat, 

 Four Bucyrus 7-foot boats. 



The 5-foot and 7-foot boats have buckets with a 

 capacity of 5 and 7 cubic feet respectively (-14 and -19 

 cubic metres). All are electrically driven, elevated, close- 

 connected bucket-line dredges of the revolving screen and 

 stacker type. Two of the boats, numbers 8 and 9, which 

 were built during 191 1, have hulls constructed entirely of 

 steel. 



