Centralia Coal Mine Dam No 8
Centralia Coal Mine Dam No 8 is an earth dam located in Lewis County, Washington, built in 1972. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Centralia Coal Mine Dam No 8
The primary purpose of Centralia Coal Mine Dam No 8 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 Transalta Centralia Mining Llc (public utility). It impounds the Tr-south Hanaford Creek near Centralia.
The dam stands 12 feet tall and stretches 470 feet across, creates a reservoir covering 13 acres, has a maximum storage capacity of 84 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1972, the structure is well into its service life at over 50 years old.
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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 03/18/2025.
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 Washington 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 | Washington |
| County | Lewis |
| Nearest City | Centralia |
| River/Stream | Tr-south Hanaford Creek |
| Coordinates | 46.70515, -122.81221 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Length | 470 ft |
| Year Completed | 1972 (54 years old) |
Storage & Hydraulics
| NID Storage | 84 acre-ft |
| Max Storage | 84 acre-ft |
| Normal Storage | 14 acre-ft |
| Surface Area | 13 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 1,310 cfs |
Ownership & Safety
| Purpose | Tailings |
| Owner | TransAlta Centralia Mining LLC |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/18/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | WA00294 |
| Federal ID | WA00294 |
| More Info | State Dam Safety Program |