Phosphate Feeds Hillsborough County

By: Mike Stevenson, Professional Geologist Team Leader, Land Excavation and Phosphate Mining Transportation & Land Development Review Division

“Phosphate feeds you” was the advertising pitch of a Florida phosphate mining company years ago. While that was perhaps true, it is especially true that phosphate feeds Hillsborough County citizens. Even though most of the mining within Hillsborough County takes place in the 4 Corners part of the county, its economic and social impact is felt all over the county from the Port of Tampa to subcontractors in Plant City.

The mining and mining-related activity is spread over approximately 55,000 acres of the county as part of the central Florida phosphate mining district. Over the past 100 years, various companies have mined and processed phosphate ore in the central Florida mining district. Currently, all Hillsborough County-based mining is operated by the Mosaic Company.

The phosphate comes from sediment that was deposited in layers on the sea floor. The phosphate-rich sediments are believed to have formed from precipitation of phosphate from seawater along with the skeletons and waste products of creatures living in the seas. Florida's phosphate rock deposits are believed to have originated in several ways. Some of the phosphate may have formed when conditions in the seawater caused dissolved phosphorus to solidify, a process scientists call precipitation. As material settled to the bottom of the shallow coastal waters, it became part of the sedimentary layers that eventually formed the sediment that is mined today. It is also likely that excrement and sea life remains played a big part in forming the deposits. Bones, teeth, and other animal remains also contributed to the ore formation.

Phosphate production begins with the mining of calcium phosphate (phosphate rock). Typically, phosphate rock is found at an average depth of 25 feet beneath the ground's surface. The surface sediment overlying the phosphate, known as overburden, consists mostly of sandy soil. The overburden is removed and stockpiled for future use in reclamation of the site. Once the overburden is removed, a matrix of phosphate pebbles, sand and clay is exposed. The material is then transported through pipelines to a beneficiation plant, where the clay and sand are separated from the phosphate rock.

The first step in separating phosphate from the clay and sand is to put the slurry in a washer where large balls of clay are mechanically disintegrated. The slurry then moves through a series of vibrating screens where fine clay particles pass through and the phosphate pebbles remain. The clay is then pumped to settling ponds while the pebbles are moved to dewatering tanks and stockpiled by conveyors for further processing. Also separated in the process is a mixture of sand and finer particles of phosphate (concentrate) that is then put through a process called flotation. In the flotation process, the mixture is put in a vessel of water where reagents such as fuel oil, soap or fatty acids are mixed in to coat the concentrate and attach air bubbles, allowing it to float, separating it from the sand. The sand is transported back to the mine and stockpiled for reclamation while the concentrate is transported to dewatering tanks and stockpiled for further processing.

When land is mined, animals, endangered species and their habitat may be destroyed. Before 1975 mining companies were allowed to mine the land and just leave when they were done. They did not have to restore the land. But in 1975, Florida passed a law that asks mining companies to restore land to its previous condition or better. This was done so that mining can go on without destroying the environment. Fixing the mined land after the mining is done is called reclamation.

The first step in reclamation is making a plan before the mining even starts. Mining companies that want to open the mine have to tell the state how they will reclaim the land after they are done. They have to record the endangered species and devise a plan of how to protect them. For example, they can relocate them while mining is going on. They also have to tell local governments about how their mine will affect the water flow and how they will make sure that the water sources are protected. Phosphate companies also have to plan how to deal with the byproducts of their operation. Reclamation is expensive, but it helps protect the environment around us.

Planning and Growth Management (PGM) permits and oversees the mining and subsequent reclamation of mined lands. PGM staff negotiates the applications and inspects the sites prior, during and post-mining to ensure compliance with Hillsborough County permit approval conditions.

Find Out More About the County’s Excavation and Phosphate Mining Review and Permitting Process

FUN FACTS

• Florida produces 75% of the USA’s phosphate and 25% of the world's phosphate.
• Phosphorus in Florida comes from fossilized remains of pre-historic animals.
• People started mining phosphate in Florida in 1880s.
• Phosphate is sometimes called "black gold."

PGM Partnering On Effort to Make University Area More Pedestrian, Bicycle and Transit-Friendly

The Planning & Growth Management Department and the Metropolitan Planning Organization have kicked off an effort to create a multi-modal transportation district in the University of South Florida area. This effort will result in a plan to make the area more pedestrian, bicycle and transit-friendly, and create opportunities for funding those improvements. The first public meeting on the project will be held on Wednesday, Sept. 9, at 6:30 p.m., at University Area Community Center, 14013 N. 22nd Street, Tampa.

The area around USF has the potential to be identified as a multi-modal district with its existing mix of residents, students and employees and the vast number of places they can access: hospitals, parks, schools, public services, commercial centers, and the university. With congested roads in the area, it is already common to see transit riders, cyclists, and pedestrians – by making those trips efficient, connected, and safe, more people will have the opportunity to choose a healthier way to travel. The proposed boundaries of the area are Sinclair Hills Road and Bearss Avenue to the north, Interstate 275 to the west, Fowler Avenue to the south, and North 56th Street to the east.

As part of this process, a group of stakeholders, which includes representatives from Hillsborough Area Regional Transit, Florida Department of Transportation, the Cities of Temple Terrace and Tampa, Senator Victor Crist’s Office, the University Area Community Development Council, University of South Florida, Tampa Bay Area Regional Transportation Authority, and others will meet periodically. The Hillsborough County Planning Commission and the Transportation Task Force also are advising on this project.

For more information, contact Ned Baier, AICP, Manager, Transportation Planning, at (813) 272-5849 or Email.

View the Complete Public Meeting Notice