National Dam Inspection Program. Cornwall Tailings Dam (NDI Number PA-00597, DER Number 38-87), Susquehanna River Basin, Bernhard Creek, Lebanon County, Pennsylvania. Phase I Inspection Report.

摘要

Cornwall Tailings Dam was constructed by the Bethlehem Mine Corporation as a settlement basin for their tailings from a nearby iron ore mine operation. The mine was closed in 1977 and the facilities of the dam are presently not in use. At the time of inspection, it was estimated that the top of the dam is approximately at elevation 908 and the pool level was at elevation 890. The U-shaped embankment is 3800 feet in length. The northern part of the embankment, which spans the original valley, is about 1900 feet long and has a maximum height of 200 feet above the downstream toe. The remainder of the embankment closes off lower areas on the east side of the reservoir with heights varying up to 60 feet. Most of the embankment was constructed from trap rock, with the exception of an impervious upstream toe and upstream blanket. There is no spillway. The only outlet is a 20-inch decant line which returned water to the mine. At present, this line is closed off near the downstream toe.