At 7:45 am on Monday December 17, the tailings dam at the former Gullbridge copper mine, central Newfoundland failed while work was under way to stabilize it. The failure resulted in a breach of the 7 m high dam approximately 25 m wide. The dam was impounding mine tailings that were partially covered by water forming a tailings pond. As a result of the failure, the pond drained completely over the next few hours, and a small amount of the tailings escaped. Small quantities of tailings pond water continue to flow from the breach.
The breach was located approximately 500 m from South Brook, a scheduled salmon river, and the source of drinking water for the community of South Brook. The water supply intake for the Town of South River is approximately 26 km downstream of the dam breach area. It is probable that most of the tailings pond water entered South Brook. Most of the escaped tailings lie within 100 m of the dam, and it appears only a small quantity reached South Brook.
Representatives from the Departments of Environment and Conservation (ENVC) and Natural Resources (NR) have been in the area since December 17th. ENVC representatives are collecting daily water samples for testing and taking daily field measurements at critical locations along South Brook. Based on the inspection of the area between the dam and South Brook by NR representatives, there are indications that tailings were carried to the river, but in limited quantities. There are a number of natural settling areas along the flow path where the tailings settled out.
In order to ensure the safety of the residents of the Town of South Brook against any potential contamination of South Brook, Medical Officer of Health issued a precautionary no-consumption advisory on December 17th. Under the non-consumption water advisory, residents were advised not drink the water or use it for cooking, washing food, brushing teeth, or making juices, baby formulas and ice. Washing clothes, washing dishes, bathing, handwashing and other non-consumptive uses were considered safe. Bottled water was made available for all residents at the South Brook Town Office. The non-consumption water advisory remained in effect until December 24, 2012.
Dam Breach – December 17, 2012
Dam Breach – December 18, 2012
Tailings Dam Debris
Dam Breach Area and South Brook
Construction of Berm for Temporary Containment and Settling Pond
South Brook Public Water Supply Intake