pip.iN.ToN.] DREDGING. 173 
Total lost time per cent. . 32. 8 
Dredging time do 67. 2 
Average number of cubic yards dredged per day of running time 2, 005 
Actual average number of cubic yards dredged per day of twenty-four hours. . 1, 347 
Summary of costs in cents per cubic yard, 1904. 
Dredge crew and power 2. 69 
Repair labor 94 
Repair supplies 1 . 61 
Superintendence 38 
Oroville and San Francisco general expense 36 
Taxes and insurance _ 48 
Bui lion expense 05 
Grand total, all costs 6. 51 
For three $45,000 dredges these items would have been as follows: 
Dredge crew and power 2. 69 
Repair labor 66 
Repair supplies 1. 61 
Superintendence ...'. 17 
Oroville and San Francisco general expense 12 
Taxes and insurance 27 
Bullion expense 05 
Grand total, all costs 5. 57 
Mr. J. P. Hutehins, of San Francisco, who has had long experience 
in the dredging fields of Oroville and has recently worked in the 
Klondike, has courteously furnished for this report an account of the 
present status of the industry, with suggestions regarding the forms 
of dredges most applicable to Alaska conditions. 
NOTES ON DREDGING. 
By J. P. Hutchins. 
Dredge mining of placer gold has been one of the most attractive 
fields for investments of capital in recent } T ears. Prospecting methods 
in use to determine the values of the areas thought to be available for 
profitable exploitation by dredging are not complicated. Until recently 
well-drilling machines have been used almost exclusively in this work, 
and in many cases the results of such sampling have led to large 
investments of capital in dredging ground and dredging machinery; 
These drilling machines have much to recommend them. They are 
cheap and mobile, can be operated on floating scows to sample river, 
lake, or sea bottoms (see PL III, J., p. 40), or used to sample a deposit 
where a large volume of water near the surface would make shaft 
sinking very costly. Numerous holes can be drilled in a short time 
and at a comparatively small cost. In many cases shafts have been 
sunk with the drill holes for centers, and the results of the two methods 
of prospecting checked well. 
It was first held that the results of dredging could be relied upon to 
equal about 50 per cent of what drill prospecting would indicate the 
