From 1955 to 1982, miners extracted millions of tons of copper ore from the Berkeley Pit in Butte, Montana. Once operations ceased, the open pit filled with toxic water. In November 1995, 342 migrating snow geese landed on the 900-foot-deep lake, now a Superfund site. Days later, they were found dead, their tracheas burned by acidic pollutants such as cadmium, lead and arsenic. (“Did toxic stew cook the goose?” HCN, 12/11/1995). Mine managers then implemented a hazing program to deter waterfowl from landing.
In early December, an estimated 10,000 snow geese landed in the Berkeley Pit to wait out a winter storm. Mine company crews, overwhelmed, could not chase them off, and thousands of birds perished. A burgeoning snow geese population and delayed migration due to unusually warm weather may have contributed to the incident. The mine companies could be fined if the Environmental Protection Agency determines they were negligent.