United States Nuclear Regulatory Commission

Office of Public Affairs

Washington, DC 20555

Phone 301-415-8200 Fax 301-415-2234

Internet:opa@nrc.gov

No. 97-164 FOR IMMEDIATE RELEASE

(Tuesday, November 4, 1997)

NRC RELEASES REMEDIATED URANIUM PROCESSING SITE

IN WYOMING FOR UNRESTRICTED USE

The Nuclear Regulatory Commission has released Western Nuclear, Inc.’s Day Loma

uranium processing site in Wyoming for unrestricted use. The agency found that the site has

been successfully remediated to meet federal requirements.

At the Day Loma site, Western Nuclear used the heap leach process to extract uranium

from low-grade ore-bearing material that was transferred from its Split Rock uranium mill, about

20 miles away.

In a heap leach process, a coated concrete or asphalt pad (like a parking lot) is placed

on the ground and crushed uranium ore is piled in a heap on top of the pad. A sprinkler is

positioned over the top of the heap, and an acid is continually sprayed over the pile. The acid

trickles through the ore (in a manner similar to a drip coffee maker) and mobilizes the uranium

and other metals into solution. The uranium is then extracted from the solution for further

processing. The remaining pile, through which the acid was poured, is considered to be a

waste product.

Western Nuclear obtained a license in 1962 for the Day Loma heap leach site, which is

located about 25 miles northeast of Jeffrey City, in an area known as the Gas Hills Region,

which is rich in naturally occurring deposits of uranium ore. Widespread activity by several

organizations involved in uranium mining and milling occurred in the region from the late 1950s

into the 1980s. Western Nuclear terminated operations at the Day Loma site in 1972, and in

1976 the Day Loma license was combined with the license for Split Rock (currently an inactive

uranium mill). In 1996, following reclamation activities at Day Loma, Western Nuclear

requested that all references to the Day Loma site be removed from the license. NRC

approved this request on October 29.

The Day Loma site is surrounded by exposed mine wastes and unreclaimed mining

lands of the Gas Hills area. Reclamation of the site was completed in 1985 under a plan

approved by the NRC. The heap leach material was placed on an impervious liner and covered

with about 8 to 13 feet of clay and random fill material. This disposal cell is designed to

minimize releases of radioactive materials to the environment.

The NRC prepared an environmental assessment of the proposed release of the site for

unrestricted use. Based on a series of conservative analyses, the assessment concluded that

potential radiation doses to members of the public from the released site would be well below

the NRC’s public dose limits and also less than the doses resulting from the naturally occurring
uranium ore deposits that surround the site.

Copies of the environmental assessment and of a technical evaluation report written by

the NRC staff are available for review and copying at the NRC Public Document Room, 2120 L

Street, N.W., Washington, DC 20555; phone: 202/634-3273.

A Federal Register notice published on October 28 describes procedures that should be

followed by persons who wish to request a hearing with respect to the technical evaluation

report and environmental assessment, which form the basis for the decision to release the Day

Loma site for unrestricted use. The requests must be filed by November 28.

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