N-4 Rockland Mine is an earth dam located in Polk County, Florida. It carries a Significant hazard potential classification.
Dam profile
NID height · 45 ft45 ft tall, taller than 90% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About N-4 Rockland Mine
The primary purpose of N-4 Rockland Mine 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 Unnamed Creek near Fort Meade.
The dam stands 45 feet tall, creates a reservoir covering 440 acres, and has a maximum storage capacity of 17,000 acre-feet.
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.
At 45 feet, this dam is taller than 90% of dams nationwide.
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Location
| State | Florida |
| County | Polk |
| Nearest City | Fort Meade |
| River/Stream | Unnamed Creek |
| Coordinates | 27.76000, -81.86000 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 45 ft |
| Dam Height | 40 ft |
Storage & Hydraulics
| NID Storage | 17,000 acre-ft |
| Max Storage | 17,000 acre-ft |
| Normal Storage | 15,400 acre-ft |
| Surface Area | 440 acres |
Ownership & Safety
| Purpose | Tailings |
| Owner | The Mosaic Company |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | No |
Identifiers
| NID ID | FL00622 |
| Federal ID | FL00622 |
| More Info | State Dam Safety Program |