59 8 APPENDIX 



North Carolina, Alabama, Mississippi, and Nevada, but these are 

 merely of low grade and not utilized at the present time. The three 

 important deposits first mentioned have been worked from ten to thirty 

 years ; the fourth is a new field which has as yet had but a small output. 



ESTIMATED LIFE OF UNITED STATES PHOSPHATE DEPOSITS 



The rate of increase in production for the last twenty years has been 

 117 per cent for each decade. Assuming that this rate of increase will 

 continue, it will require but a comparatively short time to exhaust the 

 available supply of phosphate rock in the United States. The annual 

 production, at the stated rate of increase, will be approximately 

 17,000,000 tons in 1932. 



It is hardly probable that the rate of increase in production will be so 

 great as for the last decade, since the agricultural lands of the Middle 

 West do not at present need artificial assistance. But increasing popu- 

 lation, with its accompanying intensive farming, will eventually force 

 these states to the use of fertilizing materials. The reclamation of arid 

 lands in the West will probably postpone the day, but even those lands 

 will early need some assistance to grow the large crops which will be 

 required of them. 



Of course, the vast amount of low-grade rock which is not now avail- 

 able will be in reserve, and some time before the exhaustion of the high- 

 grade phosphates we shall doubtless have begun to use this rock. The 

 increasing price of the 60 to 80 per cent phosphate will have a hastening 

 effect on the utilization of the present low-grade material. The deposits 

 of Arkansas, Georgia, North Carolina, Alabama, Tennessee, and the 

 West, which run from 30 to 50 per cent in lime phosphate, will be avail- 

 able to draw upon after the high-grade rock is exhausted. This class of 

 deposits, especially in Tennessee and the Western States, will afford an 

 enormous tonnage, but, based upon present available deposits, the life 

 of the phosphates must at best be a short one. 



FOREIGN DEPOSITS 



Deposits of phosphate rock exist in Algeria, France, New Zealand, 

 Canada, Russia, Spain, Tunis, Belgium, French Guiana, and some of 

 the South Sea Islands. The deposits of France and Belgium are practi- 

 cally exhausted, only those of low grade remaining. Concerning the 

 other countries no information as to reserve tonnage is at hand except for 

 the three South Sea Islands Ocean, Pleasant, and Makatea. These 



