IMPURITIES OF PHOSPHATE ROCK. 65 



PHOSPHATE 



CONTENTS. 



Page 



Introduction 06 



'J'he impurities that affect the market value of phosphate rock, their 



origin, character, and the methods of their elimination in mining.... 67 



Minerals of phosphate rock 67 



Associated minerals 68 



Objectionable impurities 69 



The origin of phosphate rock 71 



Original source of phosphorus 71 



. Solubility of phosphate minerals 72 



Reaccumulation of phosphate in workable deposits TZ 



Round of circulation of calcium phosphate 7Z 



Compared with calcium carbonate ^ 74 



Compared with silica 75 



illustrations of method of accumulation of phosphate deposits . . 76 



The phosphates of Florida 76 



The phosphates of Tennessee 79 



The phosphates of the western United States 80 



Phosphate deposits from guano • - 80 



Mining phosphate rock 81 



Underground mining 81 



Open pit mining 81 



Elimination of impurities and preparation for the market 82 



Washing 82 



Drying 84 



Improvements in mining methods 84 



'J"he phosphate deposits of the Southern States 86 



Production from the Southern States 86 



Description of deposits by States 86 



' South Carolina 86 



Arkansas 87 



Tennessee 88 



Florida 89 



Kentucky 91 



Virginia 92 



North Carolina .' 92 



Alabama 92 



Georgia 93 



