Number 7 is an earth dam located in Pima County, Arizona. It carries a High hazard potential classification.
Dam profile
NID height · 189 ft189 ft tall and 15,441 ft long, taller than 99% of U.S. dams with a recorded height. Height is drawn to scale against the Statue of Liberty, 305 ft ground to torch; the profile is a generic embankment section and the water level is illustrative.
About Number 7
The primary purpose of Number 7 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 Asarco Mission (private).
The dam stands 189 feet tall and stretches 15,441 feet across, and has a maximum storage capacity of 306,000 acre-feet.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Notably, no emergency action plan is currently on file for this high-hazard dam.
At 189 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Arizona dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Arizona |
| County | Pima |
| Nearest City | None |
| Coordinates | 31.89972, -111.03000 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 189 ft |
| Dam Height | 189 ft |
| Dam Length | 15,441 ft |
Storage & Hydraulics
| NID Storage | 306,000 acre-ft |
| Max Storage | 306,000 acre-ft |
Ownership & Safety
| Purpose | Tailings |
| Owner | Asarco Mission |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Emergency Action Plan | No |
Identifiers
| NID ID | AZ30037 |
| Federal ID | AZ30037 |
| More Info | State Dam Safety Program |