234 FLORIDA GEOLOGICAL SURVEY—I5TH ANNUAL REPORT 
China Clay Corporation’s plant, also near Okahumpka, the overburden 
is removed by hydraulic process. 
The method of mining this clay is very different from any com¬ 
monly employed in clay-mining. Owing to the slight topographic relief 
of the region and the proximity of the ground water-table to the surface, 
ordinary open-cut methods would be unsuccessful, and consequent¬ 
ly dredging is resorted to. After the overburden is removed, a pit 
is dug into the deposit of sand-bearing clay in which, after it is filled 
with water, a dredge is floated. The clay is then dug by dredging and 
forced through a pipe to a series of three “sand traps,” where the greater 
part of the sand is eliminated. The clay-bearing water then passes 
through a series of troughs, where it is continuously agitated, to cause 
the clay substance to remain in suspension and the impurities, which 
usually have a higher specific gravity, to settle out. From this troughing 
the clay-bearing water passes into settling vats and the water is later 
pumped off. The clay is then forced through filter-presses, where the 
excess water is pressed out. The resulting cakes of damp clay are dried 
in either steam or air-heated drying sheds, and, when dry, are ready for 
shipment. From the time the clay is first dredged until it leaves the 
filter presses, all water extracted from it, and which necessarily carries 
some clay, is conducted back to the pit. Some clay is lost, however, in 
the sand-traps and is carried out with the waste sand. 
The sand washed from the clay is used to some extent in concrete 
construction. It has been suggested that this sand could be used for 
glass manufacture, but so far as is known, no practical tests have been 
made to determine its suitability for this usage. 
DISTRIBUTION BY COUNTIES 
Occurrences of sedimentary kaolin have been noted or reported in 
the following counties: 
Alachua County —A well drilled at the gin in Hawthorne, near the 
eastern border of the county, is reported by W. S. Moore, of that place, 
to have encountered the clay-bearing sand at a depth of twelve feet. The 
thickness of the deposit it not known. This place is located only about 
eight miles west of Edgar. As occurrences of the sedimentary kaolin 
are known west and southwest of Edgar, similar deposits in the adjoin¬ 
ing portions of Alachua County are not at all improbable. 
