DREDGING FOR METALS 231 



"The Hunter dredge, working 30 days a month, excavated 106,000 

 ou.yds. of very hard material with a large number of boulders in it. 

 The cost of this month's work was as follows: 



LABOR: 



1 dredsemaster $150.00 



3 winchmen, 30 days 310.00 



3 oilers, 30 days 225.00 



2 shoremen, 30 days 120.00 



Total $805.00 



POWER: 



100,000 K.W. hours $1,000.00 



Supplies, etc 210.00 



PLANT: 



Interest, depreciation, and repairs (estimated) 1,800.00 



Total $3,815.00 



"This gives the cost per cu.yd. including our estimated allowance 

 for plant as follows: 



Labor $0.007 



Power . 009 



Supplies 0.002 



Plant.. . 0.017 



Total $0.035 



"This shows how wonderfully efficient these dredges are. It is 

 also worthy of note how small a crew operates so large a machine. 

 A company operating one or more of these dredges employs a black- 

 smith and helpers to make repairs and keep up the machinery, 

 and also a superintendent who gives the work general supervision 

 and is present at the semi-monthly clean-ups. 



"It is found that large dredges are more economical than the 

 smaller machines, and to-day the American practice is to use large 

 capacity dredges. Some of the latest machines are equipped with 

 13 ft. buckets. These are operated by the same size crew as that 

 given for the Hunter dredge, and although the cost for power 

 is larger and the charge for maintenance and depreciation is greater 

 yet the total cost is less. Some of the largest machines now built 

 have averaged 260,000 cu.ycls. of gravel per month, while some 

 have even obtained a record of 280,000 cu.yds. This would mean 

 a charge per cu.yd. for labor of only .00278 cts., a very low cost." 



The following cost data are extracted from the Mining and 

 Scientific Press and are of value, as they cover a period of years. 



