Mosaic Csa F4a
Mosaic Csa F4a is an earth dam located in Hillsborough, Florida, built in 2003. It carries a Significant hazard potential classification.
About Mosaic Csa F4a
The primary purpose of Mosaic Csa F4a is tailings. Tailings dams contain waste material from mining operations — typically a slurry of finely ground rock left over after valuable minerals have been extracted. These structures require ongoing monitoring because tailings can contain heavy metals and other contaminants. The dam is owned by The Mosaic Company (private). It impounds the Long Branch near Fort Lonesome.
The dam stands 62 feet tall and stretches 21,180 feet across, creates a reservoir covering 650 acres, has a maximum storage capacity of 37,500 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 2003, the structure is relatively new.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. An emergency action plan is in place for this dam. The most recent inspection on record was 07/20/2005. That was over 20 years ago.
At 62 feet, this dam is taller than 95% of all dams in the United States.
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Location
| State | Florida |
| County | Hillsborough |
| Nearest City | Fort Lonesome |
| River/Stream | Long Branch |
| Coordinates | 27.65000, -82.14420 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 62 ft |
| Dam Height | 60 ft |
| Dam Length | 21,180 ft |
| Year Completed | 2003 (23 years old) |
Storage & Hydraulics
| NID Storage | 37,500 acre-ft |
| Max Storage | 37,500 acre-ft |
| Normal Storage | 35,750 acre-ft |
| Surface Area | 650 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 640 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Tailings |
| Owner | THE MOSAIC COMPANY |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not Rated |
| Last Inspection | 07/20/2005 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | FL11021 |
| Federal ID | FL11021 |
| More Info | State Dam Safety Program |