368 University Geological Survey of Kansas. 
ute, produces 24 amperes at 125 volts, and maintains 100 
incandescent lights for the illumination of the plant. 
THE TAILINGS MILL. 
Directly to the rear of the power plant is the tailings mill, 
in which are installed rolls, screens, elevators, and jigs, which 
are arranged and operated in a manner similar to that em- 
ployed in a standard concentrating mill. 
The rolls are of the Cornish type, having diameters and 
width of face of 20 and 12 inches, respectively. Both Nos. 1 
and 2 rolls are run at 50 revolutions per minute. 
There is but one trommel in the tailings mill, which re- 
ceives the discharge from the chats elevator. It is 36 inches 
in diameter by 48 inches long, is covered with perforated 
metal having 1 mm. round holes, and is run at a speed of 20 
revolutions per minute. A flat screen receives the discharge 
of the dirt elevator, is 3 feet wide by 10 feet long, and is pro- 
vided with perforated metal having + mm. round holes. 
The following table gives data for the elevators operating 
in the tailings mill: 
. Height, Batter, Speed, 
Purpose. Kind. Plan, feet. aor Bucket. INCH ts sot Ethene 
DIF ty tone etic Belt and bucket, 3 X10 18 6 X< 10 1to1.5 300 
Slimesaas.ce eee s oy 3 1h 18 6 X 10 1 to1.5 300 
eed heh cerneecen se 3X 10 18 5< 8 iL (60) 163 300 
Smittemeeeeeeee % 3 X< 10 10 5x 8 TL 7x0) 1169 800 
Chatsevicccaneun 4 es 3 X10 10 BK & 1to1.5 300 
Tailings, No.1... eS 4X16 55 6 < 10 1 to 2 300 
Tailings, No.2... ef a 4X16 35 6 X 10 1 to2 300 
There are two jigs, a rougher and acleaner. The former 
has six 30x48 inch cells, which are fitted with five mesh to 
the inch brass wire screens; the latter also has six 30x48 
inch cells, which are fitted with six mesh to the inch brass 
wire screens. The length and number of strokes in the two 
jigs are 1 and { inch, and 75 and 125 per minute (150 and 
250 revolutions per minute of jig shafts), respectively. All 
the plungers of each jig are run at the same speed; 7. e., the 
shafts are not broken. 
Dertatits oF RoucHER Jig.—Owing to the difficulty experi- 
enced in handling large quantities of low grade mineral, 
such as tailings, on an ordinary multiple cell jig, a slight 
