FIRST COAL-WASHING PLANT IN IOWA 227 
the total tonnage is removed, that is, the coal, after washing, 
constitutes only about 73 per cent of the gross tonnage sub- 
jected to the washing process. Analyses of the washed coals 
show that the ash content has been decreased greatly. For ex- 
ample, the average of 41 analyses from 41 car loads of the 
washed coal by Prof. C. 0. Bates of Coe College, Cedar Eapids, 
and by reliable chemists in Chicago, was 12.75 per cent of ash. 
The average moisture content was 16.68 per cent. The lowest ash 
content was 7.62 per cent and the highest 18.43 per cent. The 
calorific value of the washed coals varies between 11,500 and 
12,500 B. t. u. These results show that the washed screenings 
are not very different in composition from the average run-of- 
mine coal of Iowa, which has an ash content of 11.63 per cent, 
a moisture content of 15.07 per cent, and a calorific value of 
11,754 B. t. u." 
The plant has a capacity of 1000 tons per day of nine hours. 
The average number of men employed is fifteen. The water 
used, about 125,000 gallons a day, is obtained from local wells 
which penetrate the sandstones of the Des Moines stage. In 
1914, the amount of screenings washed was 98,587 tons from 
which 74,595 tons of cleaned coal was obtained. 
Three grades of washed coal are sold. The grade of largest 
size, known as nut coal, is sold for domestic purposes, the other 
grades are sold for steam purposes. Mr. Timbrell states that 
these coals compete in the market chiefly with the washed coals 
of Kansas, Missouri, and Illinois, and not to any great extent 
with the unwashed coal of Iowa. 
The plant at Lakonta has demonstrated very clearly that 
screenings of Iowa coals can be washed and marketed at a 
profit. Since much of the coal of Iowa, on account of its high 
ash and sulphur content, is not suitable for the manufacture of 
coal and water gas, is somewhat destructive to grates and fire- 
boxes, and tends to disintegrate when stored, and since the evi- 
dence indicates that much of this ash and sulphur is so related 
to the coal that it can be removed by proper crushing and 
washing, is it not safe to predict that as the years go by more 
and more coal-washing plants, not only for screenings but for 
run-of-mine coal, will be established in this state? 
Geological Laboratory, 
State University op Iowa. 
Uowa Geol.- Surv., Vol. XXIV, p. 737. 
