|
Canonsburg Mill Site
Washington County, Pennsylvania
| Years of Operation |
Status of Mill
or Plant Site |
Uranium Ore
Processed
(Million Short Tons) |
Production
(Million Pounds U3O8) |
| 1911-1922, 1930-1942, 1942-1957 |
Decommissioned |
-- |
-- |
Mill/Plant Area
(Acres) |
Disposal Cell
Area
(Acres) |
Disposal Cell
Radioactive
Waste
Volume
(Million Cubic Yards) |
Disposal Cell
Total Radioactivity
(Ci, 226Ra) |
Disposal Cell
Average Tailings
Radioactivity
(pCi/g, 226Ra) |
UMTRA Project
Final Cost
(Million Dollars) |
| 34 |
6 |
0.19 |
100 |
2,315 |
47.59 |
Location: The Canonsburg mill site is located in the Borough of Canonsburg, Washington County, Pennsylvania.
Background: From 1911 to 1922, the Standard Chemical Company operated a radium extraction plant on a 19-acre site in Canonsburg. Between 1930-1942, uranium and radium salts were extracted at the Canonsburg plant from residues and uranium ore. From 1942 to 1957, Vitro Manufacturing Company (later the Vitro Corporation of America) operated a mill at the site to recover uranium and rare metals from various ores and onsite residues, government-owned uranium ore, process concentrates, and scrap materials. The uranium concentrates produced by Vitro were sold to the U.S. Government. The waste products that accumulated at the site over its long history include residues generated by the incomplete extraction of radium, uranium, and other metals during processing of ore, byproduct chemical precipitates such as iron oxides and gypsum, process solutions, raw unprocessed ore materials, and uranium mill tailings. The total quantity of uranium/radium-bearing materials that were processed at the Canonsburg site during the periods of operation is not readily calculated based on the total radioactive waste volumes reported in the literature for the Canonsburg and Burrell sites. The uranium mill tailings were initially stored in uncovered piles, and the tailings material became dispersed by wind and water erosion. Some tailings material were also removed from the mill site for use as fill in local and regional construction projects. In 1956 and 1957, about 11,600 tons of mill tailings from the Canonsburg site were relocated to a railroad property near Blairsville in Burrell Township, Pennsylvania. After the Vitro uranium mill was closed down in 1957, the site was used until about 1966 as a storage facility under a contract issued by the Atomic Energy Commission. The land was purchased in 1967 by private interests and eventually became the Canon Industrial Park, a commercial park for light industrial use.
|
UMTRA Surface Remediation: Remedial action began in October 1983 and was completed in December 1985. The expanded Canonsburg (Vitro) mill site, located in a residential area, includes a 34-acre tract that incorporates the former property used by the Vitro mill and also several adjacent private properties. Detailed radiological surveying of the site revealed that large quantities of radioactive wastes generated during radium and uranium recovery operations remained on the site. Contamination by radium materials extended locally to more than 16 feet below the surface. In response to local public concern, most of the site’s radioactively contaminated materials were stabilized in place. Remediation work at the Vitro mill site included stabilizing about 192,000 cubic yards of onsite radioactive materials and the decontamination and cleanup of nearby vicinity properties including several residences. In all, 163 vicinity properties were identified and cleaned up: radioactively contaminated soil was excavated and clean backfill material was used in grading the properties for proper drainage. Contaminated material removed from vicinity properties was returned to the Vitro mill site and stabilized there along with the in situ residual material.
Disposal
Area: At the Vitro site, the residual radioactive
materials were consolidated into a 6-acre disposal cell in1985. The cell
is lined with a one-foot thick clay layer designed to minimize percolation
of water through the cell and thereby protect local groundwater reservoirs.
The engineered, multilayered cap of the disposal cell is six-feet thick
and consists of: a three-foot-thick soil and clay barrier designed to
prevent the escape of radon gas; a riprap layer up to two feet thick covers
the radon barrier and serves as erosion protection; and a one-foot-thick
soil layer planted with native grass species covers the cell.
Responsibility
for Remediation: U.S. Government, 90 percent, and
Commonwealth of Pennsylvania, 10 percent.
Stewardship: The
Canonsburg site is being managed under the U.S. Department of Energy’s
(DOE) Long-Term Surveillance and Monitoring Program (LTSM) in accordance
with the approved site specific plan.
Groundwater Program:
In 1996, the Canonsburg site was placed under the general license issued
by NRC for custody and care of residual radioactive disposal sites, and
the site was transferred to the LTSM Program. Groundwater covering an area
of about 78 acres in the vicinity of the Canonsburg site is contaminated
with wastes from ore processing. There are no known human uses of groundwater
in the vicinity of the disposal site. Surface water is the major water source
used by public water systems in Washington County, Pennsylvania. To evaluate
contaminant concentration trends within the unconsolidated strata underlying
the site, DOE will continue to perform annual limited monitoring of groundwater
and surface water through 2003 as a “best management practice.” Monitoring
of groundwater for uranium is expected to continue in perpetuity, with annual
surface water monitoring to be performed at three locations.
|
|
