Tennessee Phosphate Industry. 79 



with a hole in the center, which are themselves discharged inter- 

 mittently by an attendant. The phosphate-sand, of course, piles 

 around this central hole, so as to form a cone, and in effect the 

 boxes are pyramids instead of cubes. These discharge on to the 

 wet storage pile, which is not covered over. After drainage in 

 this pile the rock is fed to driers of the ordinary rotary type, and 

 from the driers is lifted to a tower, in which is set a sizing screen, 

 by which the product is made into two sizes, lump, pebble and 

 sand. This plant appears to be designed on systematic lines, and 

 the company claims excellent results from its operation of about 

 twelve months. 



It is obvious that this process has brought into use, or can bring 

 into use, deposits that were unavailable under the old methods, 

 and that it has further greatly conserved the supply of phosphate 

 rock in Tennessee. As a matter of fact, a not inconsiderable pro- 

 portion of the production of the past few years has been obtained 

 from settling ponds, a photograph of one of which is here shown. 

 I estimate that something like 200,000 tons of material has been 

 taken from this pond since this work was begun. It is further 

 obvious that if a practical method of screening phosphates can be 

 devised it may be possible to use this process or an analogous one 

 in bringing into use very large deposits of sandy phosphatic ma- 

 terial which cannot now be used. 



In the latter connection it is to be noted that such material is 

 very abundant throughout a large part of the Middle Basin of 

 Tennessee. It differs from the deposits consisting chiefly of phos- 

 phate sands in being of a lower grade, not decayed, and in con- 

 taining considerable silicious sand. The method is not so promis- 

 ing, therefore, for such deposits as for the thoroughly weathered 

 deposits, but at this moment offers possibly the best starting point 

 for experiments in utilizing such low grade material. 



It may be remarked at this point that the actual phosphate re- 

 sources of Tennessee are ample for any call upon them which can 

 be foreseen within any reasonable length of time, provided these 

 low grade phosphate deposits can be utilized. They cover areas 

 of hundreds of square miles, and exist as unaltered phosphatic 

 limestone ranging in content of phosphorus from six to ten or 

 twelve per cent. Sundry methods for the utilization of this ma- 

 terial have been proposed. The efficacy of ground limestone has 



