AJAX-HECTOR MINE POND - MN00000-3262
Dam Name: AJAX-HECTOR MINE POND
State: MN
Downstream Hazard Potential:
Incident Type: Failure
Incident Date: 04/24/2018
Incident Driver: Hydrologic/Flooding
Incident Mechanism 1: Animal Activity
Incident Mechanism 2Debris Clogging
Incident Mechanism 3Overtopping
Incident IDMN00000-3262
Incident DescriptionTributary stream meandered into abandoned mine pit during spring snowmelt causing partially filled mine pit to completely fill and overtop natural earth embankment. Embankment failed, draining pit into the Embarass River and causing damage to utilities and water quality issues on Embarass Lake.
Named Hydrologic Event
EAP Enacted (Y/N) due to IncidentNo
Fatalities (Number)0
Number of People Evacuated0
Number of Habitable Structures Evacuated0
Number of Habitable Structures Flooded0
Other Infrastructure ImpactsOther
Economic Damages (in $)$100,000 to $500,000
ResponseProperty was abandoned by mining company decades ago and is now owned by state (IRRRB). Rebuild of trail over $1,000,000.
Volume released at failure (ac-ft)100
Additional Remarks or UpdatesThe "dam" is a 250 foot section of natural ground between an excavation related to the mine pit and an excavation related to the diversion channel of the Embarrass River. Damage to Utility (power, telephone, water supply and sewer) lines severed. Tailings and raw sewage from severed sewer line entered lake downstream of embankment failure. Paved trail washed out.
Owner TypeS
Dam TypeOT
Primary Purpose(s)O
EAPNR
Dam Height55 ft
Max Storage (ac-ft)150.00
Surface Area (acres)9.00
Year Completed1945
NID NumberMN00000
River NameOS TRIBUTARY TO THE EMBARRASS RIVER DIVERSION
Latitude47.541
Longitude-92.3108
Year Modified
Regulatory Agency(ies)MNDNR
Incident Time
Incident Duration1 day
Incident Report ProducedUnknown
Information SourcesMNDNR
