﻿REPORT ON THE PHOSPHATE FIELDS OF SOUTH CAROLINA. 9 



These numerous and widely varying factors make it very difficult 

 to strike an average for the cost of producing high-grade South 

 Carolina phosphate, but the following figures, compiled from data 

 obtained in these fields and from the author's own observation, are 

 probably as close approximations as can be obtained. 



Talle III. — Average cost per ton of producing South Carolina phosphate. 



Hem. 



Labor in mining 



Labor on washer 



Labor on dryer 



Haulage 



Fuel for power plant . . 

 Fuel for drying rock... 

 Interest on investment 



Expense. 



SI. 50 

 .10 

 .05 

 .30 

 .04 

 .12 

 .40 



Expense. 



Insurance 



Taxes 



Overhead charges 

 Depreciation 



Total 



$0. 05 

 .05 

 .10 

 .75 



3.46 



WASTE MATERIAL. 



In mining and preparing South Carolina rock for the market the 

 same sources of waste are encountered as in the production of Florida 

 phosphate. The loss of finely divided phosphate (held in suspension 

 and passing through the cylinder screens) incident to the present 

 method of cleaning the rock is very great, though not as great propor- 

 tionally as the loss in washing the Florida product. 1 The phosphate 

 stratum will yield on an average about 40 per cent phosphate rock; 

 the remaining 60 per cent, consisting of sand, clay, and finely divided 

 phosphate, is discharged upon the waste heaps. An analysis of mate- 

 rial from the dumps made by the Bureau of Soils showed a content of 

 about 13 per cent bone phosphate of lime, which means that over 20 

 pe~ cent of the phosphate taken from the mines is discarded. An- 

 other, though minor, source of waste is at the picking board or belt 

 where the clay balls, marl, etc., are removed by hand Inexperienced 

 and careless pickers frequently throw away much good material. 



DISPOSAL OF PRODUCT. 



Although some specimens of South Carolina rock contain as high 

 as 75 per cent of bone phosphate of lime, the average grade of 

 the marketed product is about 61 per cent. Almost the entire 

 output is sold in the State on a guaranty of 60 per cent of bone 

 phosphate and made into acid phosphate by the local factories. 

 The present price of South Carolina rock f. o. b. at the mines is 

 about $4 per ton. 



Some rock is shipped to neighboring States and a small amount 

 as far north as Richmond, Va., but the freight rates will hardly 

 admit of its shipment any great distance. The price of the higher 

 grade Tennessee and Florida phosphate f. o. b. at the mines is so 



i Waggaman, Bui. No. 76, Bureau of Soils, U. S. Dept. Agr. (1911). 



