A Survey Of Current Open Pit Practices In Florida Phosphate

The three basic ingredients of fertilizers are nitrogen, phosphorus, and potassium. Nitrogen comes from natural gas or other sources and is usually a "manufactured" ingredient. Phosphorus and potassium come from mineral sources which are mined in open pit and underground mines all over the world. Phosphorus is one of the 15 chemical elements needed to sustain life. Along with nitrogen and potassium, it is essential to the fertility of the soil and to the growth of plant life. Plants require phosphorus for proper soil conditions, early root formation, and crop maturity. Humans and animals require phosphorus for bone and tooth development. The primary raw material for phosphorous fertilizers is phosphate rock. It is found and mined in many areas of the world. Morocco, the United States, USSR, Tunisia, and some Pacific Islands are the leading rock producers. Other sources of phosphate are guano, bone meal, and other natural organics, but these comprise a very small percentage of all phosphate used. Phosphate rock in the United States is mined in Florida, North Carolina, Tennessee, Idaho, and Montana. Florida alone produces about 70% of all the rock mined in this country, mostly from a 20 X 30 mile area in Polk and Hillsborough Counties in central Florida known as the Bone Valley district. There are phosphate reserves in many parts of Florida, and within the past three years mining has begun in north Florida in Hamilton Country (see Fig. 1). In 1967, world phosphate rock production was about 75 million short tons (st). The United States produced about 35 million st (about 47%) of which Florida produced about 25 million st (about one-third of world production). According to Phosphorus and Potassium magazine (Mar./