For decades, it has been said that the phosphate in Florida could be mined for about another 25 years. Technological advances and market changes, however, have continually lengthened the expected life of phosphate mining, allowing mining of rock that wouldn’t have been mined in previous years.
The Hawthorne Formation, which contains much of the Florida phosphate deposits, covers much of the Atlantic Coastal Plain of the southeastern United States. In the heart of the Central Florida phosphate district, the Bone Valley Formation overlays the Hawthorn Formation. The two are separated by a limestone layer of varying thickness. It is the Bone Valley Formation that has produced the majority of mining activity in central Florida to date. The Hawthorne Formation is being mined in North Florida. It is also the Hawthorne Formation that is being mined in the southern extension of the central Florida phosphate district.
Florida phosphate reserves alone contain about 10 billion tons of soluble phosphate rock. Based on the current mining rate in Florida, this would last more than 300 years if economic and technological conditions allow.
As we look to the future of phosphate mining in Florida many factors must be considered. For example, in the future it may take less phosphate to fertilize the earth because technological advances may result in more efficient fertilizers that could deliver nutrients to plants only when they need them. Such fertilizers would provide the added benefit of reducing the amount of nutrient runoff into surface and ground water.
Many say the factor limiting phosphate mining in Florida is not the deposit, but the number of people migrating to the state and the development they would require. There is a deposit around the Boyette area in Hillsborough County, for example, that will likely never be mined because the land over it has been developed.
In the future, technological advances and market conditions may lead us to other deposits that would not be considered today. There are large deposits offshore that have formed in the Atlantic and extensive deposits in the Western United States that are too remote to economically mine today.