PHOSPHATE ROCK: UTILIZATION AS FERTILIZER. i 
cent tricalcium phosphate, with only very small percentages of iron 
and aluminum oxides. The average cost of mining the western 
phosphate is from $1.50 to $2 a ton. 
Because of their great distance from the fertilizer market, the 
western deposits have been mined to a very small extent, but the 
tonnage of high-grade rock in this region far surpasses that of any 
other area yet discovered. 
THE PHOSPHATES OF ARKANSAS. 
The phosphates of Arkansas are not generally considered of great 
economic importance, for, though small bodies of high-grade rock 
have been found in several localities, the average phosphate content 
is far below that of the rock mined in Tennessee and Florida. 
Mining has been conducted to a considerable extent only in the 
northern part of the State, in Independence County, about 12 miles 
from Batesville, a town on the Missouri Pacific Railway. Here the 
phosphate rock is of Silurian age and occurs in two strata, one 
directly overlying the other. The upper stratum (from 34 to 6 
feet thick) is the only one considered worth mining, and averages 
about 55 per cent tricalcium phosphate, with 5 or 6 per cent of the 
combined oxides of iron and aluminum. No mining has been done 
in these fields for over a year, since it has been found more economical 
to supply the demand for phosphate from the richer deposits of 
Tennessee. 
The mining of Arkansas phosphate was conducted in a manner 
similar to the mining of Tennessee blue-rock phosphate, and the 
cost of extracting it was approximately the same. 
KENTUCKY PHOSPHATE. 
Several small deposits of high-grade phosphate rock have been 
found in the Ordovician lhmestone in Woodford, Scott, Fayette, and 
Jessamine Counties, Ky. 
The phosphate occurs in thin, close-grained plates, brownish gray 
in color, and resembles closely the brown-rock phosphate of Ten- 
nessee. In order to prepare a high-grade product, the material must 
be put through a washing process like that employed in the brown- 
rock fields. The cleaned product varies in its content of tricalcium 
phosphate from 60 to 75 per cent. 
A small amount of development work has been done and a small 
tonnage shipped from Midway, a little town on the Louisville & 
Nashville Railroad between Frankfort and Lexington, Ky. So far 
all the rock sold has been finely ground for direct application to the 
field. 
