258 University Geological Survey of Kansas. 
with the larger mills, being one of the essentials of a hand- 
jigging plant, but are gradually coming into more general 
use, and are being introduced into the large concentrating 
works. Figure 2, plate XLII. | 
Chutes.— Chutes contain the bar screens or grizzlies, and 
are seldom more than ten to twelve feet long, and support 
the bars at an angle of about forty-five degrees with the tram- 
way, with which they are connected. In figure 37, a tram- 
way, A, and chute, B, are shown. The steep inclination is 
given to insure the complete passage of the oversize material 
through the chute, as the material screened is often wet and 
argillaceous, and therefore very apt to clog. However, siz- 
ing becomes more and more imperfect as the inclination of 
the screen surface increases in steepness. 
The chute consists of two side planks, generally 2x12 inch 
oak. The upper one-third and occasionally a foot of the 
lower end of the floor of the chute is also lined with oak plank. 
In some cases the middle one-half of the floor of the chute is 
barred. The chute is usually two and one-half to three feet 
wide. At the top a cross timber is placed and firmly sup- 
ported by the framework of the chute, which is intended to 
catch the bucket, when it is dumped from the car, X, figure 
37. This holds the bucket with the opening or mouth 
downward, in which position it may be jolted to loosen any 
dirt or boulders that may adhere to or clog in it. When 
emptied, it is drawn back in place upon the car by hand. 
The chute is supported at the upperend through the tramway 
timbers, O, and at the lower end by two upright posts, Z. 
On the shaft side of. the post Z, a partition, P, is built up of 
hardwood board or plank, and keeps separate the lump and 
fine dirt. | | 
Parallel Bar Screens.—The screen proper consists of iron 
rods ranging from three-fourths to one inch in diameter, and 
from four and one-half to five feet in length. Figure 46. 
There are several different ways of fastening the rods to the 
chute timbers. The two methods most commonly employed 
are shown at /and 2. In 7, one end of a rod is flattened, 
and has a hole punched in it, which end is bolted to the plank 
