20 GRAVEL AND PLACER MINING IN ALASKA. [bull. 263. 
3. How deep will buckets or dipper dig? 
4. What is capacity of buckets? 
5. What are arrangements for moving dredge and holding it in place? 
6. How is gravel sized? 
7. Are plates or quicksilver used? 
8. What is the life of wearing parts? 
9. What kind of power and engines are used? 
10. What fuel is used, and what is its cost? 
11. What type of pumps are used, and what is their capacity? 
12. How many cubic yards of gravel have been handled in a given time from past 
record? 
13. What special difficulties are encountered? 
14. What is cost of dredging under local conditions? 
15. Is frozen ground encountered, and if so, how does dredger work in it? 
In case of special operations not covered by the above summary, will you kindly 
give brief descriptions, especially of apparatus which has proved successful in han- 
dling placer gravel under northern conditions? 
The following space is left blank in order that any special description of the 
property may be given. 
You are requested to fill out this schedule as soon as possible and return in the 
inclosed envelope which requires no stamps. 
Forms 2, 3, 4, 5, 6, contained the first thirty-four questions in form 
1, and the questions in form 1 regarding prospecting ground. In addi- 
tion the following data were asked for, a separate form being used 
according as the operations came under the heads of hydraulic mining, 
dredging, open cutting, or drift mining. 
Form 2. — Hydraulic mining. 
Size of head-gate. 
Dimensions, grade, length, capacity, and cost of head ditch. 
Cost of maintaining. 
Length of flume, if any. 
Dimensions, grade, and size of lumber in bottom, sides, and battening; size an( 
length of posts and sills in head flume; number of collars to box. 
Amount of trestling and cost of same. Size of sills, posts, and stringers. 
Is flume or ditch covered to prevent freezing? Describe method. 
Number of relief gates in ditch line. 
Are inverted siphons used? If so describe. 
Amount of water available. 
Size pressure box and size lumber used. 
Head of water in feet. 
Length of pipe line from pressure box. 
If more than one pressure box or pipe line, describe. 
Size, gage, cost, and nature of pipe employed. 
Where obtained. 
Kind of joints. 
Kind and number of air valves. 
Method of setting and unsetting pipe. 
Size of pipe at giant or giants. 
Is water diverted for other purposes beside giant? 
If so, how much, and for what purposes? 
Number and angles of elbows in main pipe line. 
