Phosphate Mining Overview

  • Mar 23, 2010
  • Greg Blanchard
Phosphate Dragline

Phosphate mining has occurred in the state of Florida since the late 1800s. This site provides a short summary of the phosphate industry in Manatee County

Why mine phosphate in Manatee County?

Millions of years ago, when the ocean flooded Florida, a layer of sand and clay rich in tiny phosphate particles was deposited. This large deposit of phosphate rock became known as the Bone Valley due to the amount of fossils found among the rock. A portion of the Bone Valley lies in Manatee County. There are only few areas of phosphate deposits in the United States. In fact, central Florida is estimated to contain 80 percent of the United States’ phosphate deposits.

 

Phosphate is a limited resource. It cannot be replaced. As land is farmed the soils become nutrient deficient and must be replenished in order to produce. Therefore, most of phosphate mined (90%) is used to make fertilizer; the remainder is used to make animal feed supplements, and additives in such products as toothpaste and soft drinks.

 
Phosphate and overlying deposits are rich in fossils. These fossils are from the Pleistocene, Pliocene, Miocene and Oligocene time periods (2 - 35 million years ago) and contain many large land vertebrates and shallow sea creatures. Specimens may be viewed at the Mulberry Phosphate Museum in central Florida.
 

Where is phosphate mining occurring in Manatee County?

Refer to Mosaic Fertilizer, Inc. Property Ownership Map.(link to map)

Mining Techniques

The phosphate deposits occur anywhere between 30 and 50 feet below the ground surface. Due to the relative shallow depths of the deposits and the structure of the layer above it (i.e., mostly unconsolidated sand and clay), the phosphate matrix consisting of phosphate rock, sand and clay, is extracted through a process known as strip mining. The layers above the phosphate matrix (overburden) are removed by large earthmoving machines known as draglines and placed to the side. The phosphate matrix is then extracted and placed in slurry of water to transport to the beneficiation plant via a network of pipes. Finally, sand that has been removed by the beneficiation plant and the overburden are returned to the voids created by the mining process. Clays are placed in settling facilities known as clay settling areas. 

 

Another method utilized in Manatee County is referred to as dredging. This excavation method is carried out mostly underwater using a cutter-suction dredge. This method uses both an overburden dredge and a matrix dredge to uncover and extract the phosphate matrix.
 

Beneficiation

Beneficiation means separating a wanted mineral from other material that is also contained in the matrix. In the case of phosphate, this means separating clay and sand from the phosphate rock. A mechanical process called washing and screening is used to separate the larger phosphate pebbles from the ore. A process called flotation is used to recover the finer particles of phosphate from the sand. The sand is pumped back to the mine cuts for reclamation. The clay is pumped to clay settling ponds for long-term storage.

Mining Rules & Regulations

Phosphate mining is extensively regulated at the federal, state and local levels. Applications of Conceptual Mine Plans and Reclamation Plans and NPDES applications are reviewed and processed by the Florida Department of Environmental Protection, Bureau of Mining and Mineral Regulations. Dredge and Fill applications are submitted to the U. S. Army Corps of Engineers. The Tampa Bay Regional Planning Council reviews the Development of Regional Impact (DRI). Consumptive uses of water, construction and regulation of wells, and management and storage of surface waters are regulated by the Water Management District.

Manatee County’s general authority to regulate phosphate mining is set forth in Chapter 2 and Chapter 3 of the Comprehensive Plan.  Prior to mining, an applicant must receive approval of a Development Order, Rezone, and Master Mining Plan & Operating Permit. Public Hearings are conducted for all major mining approvals.
 
Phosphate Mining Ordinance (Ordinance No. 81-22), effective October 1981, laid the procedure for permitting phosphate mining in Manatee County. It includes financial responsibility requirements, master mining plan application submittal requirements, operating permit application submittal criteria, reporting requirements, standards for radiation, and criteria for mining activities, among other items. The provisions of Ordinance No. 81-22 are restated in the new Phosphate Mining Code and are still enforced today on all mines active prior to July 1, 2004, or for which applications were filed by that date.
 
Phosphate Mining Code (Ordinance No. 04-39), adopted November 2, 2004, reflects advances in knowledge and technology related to mining and reclamation and is designed to provide protection of adjacent property from adverse impacts, protection of water quality and protection of water quantity during and after mining. Changes include additional financial responsibilities of the mining company, administrative enforcement procedures, cumulative impacts assessments, and reclamation success criteria as further detailed in Manatee County’s Phosphate Mining Reclamation Manual (Appendix E of Ordinance No. 04-39).
 
Master Mining Plan – A Board of County Commissioners approved plan, through an adopted resolution, that provides a description of pre-mining, mining and post mining and reclamation activities over the life of a mine.  
 
Operating Permit – The written authorization, granted by the Board of County Commissioners through an adopted resolution, for an applicant to proceed with specified phosphate mining activities, in accordance with the Master Mining Plan, for a specified period of time.
 

Reclamation

Since July 1, 1975, the phosphate industry has been required to reclaim all mined lands according to Florida law. The mining company must return the lands to beneficial uses in accordance with their permit approvals.

 
As set forth is in Chapter 378, Florida Statutes (F.S.), the Florida Department of Environmental Protection, Bureau of Mining and Mineral Regulations, administers the Mandatory Phosphate Mine Reclamation Code, Chapter 62C-16, Florida Administrative Code (F.A.C.). Mandatory Phosphate Reclamation Code requires that wetlands and natural surface waters that are disturbed by phosphate mining site preparation or phosphate mining operations be restored at least acre-for-acre and type-for-type. The Bureau of Mining and Mineral Regulations has developed the Integrated Habitat Network (IHN) plan as a focus for the reclamation and permitting efforts for phosphate mining in Central Florida. The IHN provides for the preservation of natural communities adjacent to major river systems and their tributaries and construction of wildlife corridors to be associated with these communities, thereby affording wildlife and native seed sources the ability to access reclaimed lands.
 
Manatee County’s Phosphate Mining Reclamation Manual (Ordinance 04-39, Appendix E) is designed to protect the surrounding environment and ensure reclamation of the area of land affected by mining. This manual defines the types of mined/disturbed lands to be reclaimed, establishes performance standards for reclaiming land and establishes release criteria for post-reclamation for uplands as well as wetland community types.