Pangea Group

Client:

U. S. Department of the Interior, Bureau of Reclamation

Scope Of Work

Pangea was contracted by The Department of Interior, Bureau of Reclamation (Reclamation) to provide work and services for the removal of Man-Made Features (MFR) in the Upper Mine Area of Operable Unit 1 of the Orphan Mine Site in Grand Canyon National Park, Arizona The MFR was the first step of an EE/CA commissioned by the National Park Service for remediation and removal of an abandoned Uranium Mine on the south rim of the Grand Canyon. The removal featured the demolition of a 70-foot tall headframe structure extending over the edge of the canyon as well as the removal of several dozen radiologically contaminated structures spread over a 3-acre site. A total of 22 Man-Made Features and 5 Debris Concentration Areas were removed, making for more than 1600 tons of features removed. These Features consisted of the Head-Frame structure, mining-related equipment, buildings abandoned on site, debris both on the site footprint and over the edge of the canyon, and a small amount of non-mining related items. Other work activities under this contract included an initial site scoping evaluation, building a project specific concrete decon pad, as well as waste characterization, profiling, transportation, and disposal, of over 1000 tons of radiologically contaminated waste.

The demolition and removal of the headframe structure involved two 140 ton extended-boom cranes, a specialty rigging subcontractor to disassemble the structure without torches, rope access technicians performing removal operations over a 1600 ft vertical shaft, and installation of a steel cap for closure of the mine shaft. 
Pangea’s technical climbers were able to place a 300-foot safety/debris netting across the mouth of the canyon preventing the possibility of lost material and ensuring workers near the edge had safe platform from which to perform work. Pangea employed certified wilderness climbers for this work over the rim to assure a safe project with this high-risk aspect of the project.

Wastes were screened, segregated, surveyed, and placed into waste containers in an efficient manner that minimized the ability of the unique canyon weather to interrupt the project schedule while minimizing the amount of waste requiring radiological disposal. Radiological survey data was also gathered on various members of the headframe for a dose reconstruction model of the tower, to be completed later this year. While the project yielded over 1000 tons of radiologically contaminated material, Pangea was able to employ an innovative characterization approach that allowed large cost savings through the use of an alternate disposal facility.

All work had to be completed during the winter months in order to avoid disturbing the California Condor and Spotted Owl nesting seasons.