GRAND CANYON, Ariz. - Last summer's radiological testing at Grand Canyon School puts to rest the rumors that uranium mine fill was used in construction of the sports fields.
According to the final report, which was released last week, radiation levels on school grounds were indistinguishable from those in background areas.
"There is no indication (and it is, therefore, very unlikely) that uranium-bearing waste rock is present in the soils underlying the athletic field area," the report said.
Park Superintendent Steve Martin called for the testing in response to longstanding rumors that fill from the Orphan Mine and others in the area were used in the fields.
Engineers from URS Corp. were on the grounds for four days in late July to measure both gamma ray levels and take soil samples to test for the presence of radium 226.
In all, they took nearly 29,000 gamma readings and collected soil from 200 locations, down to two feet below the surface.
Analysis showed the levels to be "typical of the region as a whole."
Had levels been elevated, the next steps would have been to evaluate the health risk and plan for removal if needed.
In a review of their own construction records, the Park Service found no documentation that mine tailings were used in construction.
The claim for the Orphan Mine was staked in 1906. While it was mined some for copper, its most productive years were between 1953 and 1969, when it closed after yielding 13 million pounds of uranium.
The government assumed ownership of the site in 1987. Man-made features were removed last fall and planning is under way to determine the scope and cost of cleanup.