62 
PRELIMINARY REPORT ON COAL-TESTING PLANT, [bull. 261. 
The next important item in successful washing is the determination 
of the amount of coal retained in the refuse or, in other words, 
wasted. From the composition of the refuse and its weight the amount 
of coal in the refuse is about 1,000 pounds, or about 3^ per cent of the 
original charge, or about 5-J- per cent of the coal in the original charge. 
The effect of washing in improving the quality of this coal is shown 
by steam tests Nos. 18 and 19. Test No. 18 was made on lump coal 
from this mine, and test No. 19 was made on the washed slack from 
the same mine. 
The following brief results of these tests are given: 
Steam tests of lump and washed coal (Illinois No. 2). 
Coal tested. 
Lump coal 
Washed slack. 
Total 
coal con- 
sumed. 
Horse- 
power de- 
veloped 
by boiler. 
Dry coal 
burned 
per square 
foot of 
grate sur- 
face, per 
hour. 
Equiva- 
lent evap- 
oration 
from and 
at 212° F. 
per pound 
of dry 
coal. 
Dry coal 
per indi- 
cated 
horse- 
power 
hour. 
Dry coal 
per electri- 
cal horse- 
power 
hour. 
Pounds. 
11, 124 
10, 096 
Pounds. 
211.4 
210. J 
Pounds. 
24.90 
22.36 
Pounds. 
7.21 
8.00 
Pounds. 
3.92 
3.54 
Pounds. 
4.85 
4.38 
A small amount of this coal was also washed for coking purposes, 
and the improvement ma} T be noted by comparing the results obtained 
from this charge with those obtained from a charge of Illinois No. 1, 
which consists of lump coal from the same mine. This test was made 
on a charge of 9,000 pounds of unwashed coal, which was burned for 
48 hours. It produced some small pieces of coke mixed with charred 
coal and ash. This coal contained 15.95 per cent of ash, and probably 
for this reason failed to coke. 
The second test was made on Illinois No. 2 washed. The amount oi 
coal charged was 9,000 pounds, which, after burning 64 hours, yieldec 
3,389 pounds of mixed hard and soft coke and 352 pounds of breez< 
and ash. 
From this report it is obvious that the raw lump coal did not coke 
but the washed slack produced coke of fair quality, although th 
percentage of the yield is so small that it probably would not be com 
mercially successful. 
The improvement by washing is also shown by the chemical analyse 
of the coal before and after washing, as follows: 
