254 University Geological Survey of Kansas. 
exposed on the surface is slight, as it is exposed to the light 
and air and is also being constantly rubbed by its passage 
through the hoister’s leather mit while hoisting. The life of 
a cable is, by the use of preservatives, often doubled and 
trebled. : 
Dumping MAcHINERY.— Dumping machinery proper is con- 
fined to buckets, dumping boards, and cars. ° 
New systems of automatic dumping may be introduced 
with deep mining—that is, when cages and cars are em- 
ployed—but as long as buckets are used no great change from 
the present methods may be looked for, as those now in com- 
mon use are easily operated. 
The act of dumping, when buckets are employed, is per- 
formed wholly by means of the bucket and a combination of 
ropes; the dumping board simply guides the dumped ma- 
terial in the proper direction. Several of the more common 
methods of dumping by bucket are as follows: In 7, figure 
41, is shown a tub or bucket filled and hoisted to the top by 
the rope #. The broken lines represent the rope F, which 
bears the hook, H, before it is fastened to the loop, C, at the 
bottom of the tub. The solid lines show the rope F when 
hooked, preparatory to dumping, which operation is per- 
formed by the hoister. On reversing the drum, the rope L 
lengthens, while the rope / remains of the same length. 
The result is the reversing of the ends of the tub, as seen in 
2, After dumping the hoisting drum is again reversed (in 
this instance set to rotating in the same direction as when 
hoisting), thus shortening the rope H, which rights the tub. 
The rope Fis then unhooked from the bottom of the tub, 
whereupon the tub is free to descend to the pit. 
Another form of bucket dump is shown in figure 39. In 
this case the latch or trip, a, is pushed back (to the left) ; 
the same push starting the bucket to dump, which is done 
automatically, by gravity. (See description of the bucket.) 
When emptied, the lower part being the heavier, the bucket 
will right itself, and, in so doing, will set the latch when the 
bucket has assumed an upright position. 
Still another form of self-dumping bucket is shown in 
figure 40. When the bucket reaches a position for dumping, 
