Wyoming has the largest reserves of uranium in the United States. Significant uranium deposits were first discovered in the early 1950’s following a post war boom driven by the formation of the Atomic Energy Commission (AEC). Commercial open-pit mining really took hold in the mid-1950s, leading to underground and open pit mining in the 1960’s and 1970’s, followed by heap leach extraction and in-situ recovery (ISR) dominating the extraction method in the 1990’s and current. During the 1950s through 1970’s, some of the most productive mines were located in the Gas Hills of eastern Fremont County, about 70 miles west of Casper and 50 miles east of Riverton, Wyoming. As with most extractive operations, uranium mining in Wyoming went through “boom and bust” cycles leaving ghost towns and abandoned mines in its wake. As part of the uranium industry, uranium mills and mill processing were part of the landscape. Whereas the State of Wyoming regulated mining, the US Nuclear Regulatory Commission (NRC) regulated uranium processing and mill tailings.
In an effort to ensure mine and mill reclamation, both agencies required the Company to post a reclamation bond. Typically, and as was common with older facilities, these bonds were inadequate to achieve modern reclamation standards. Wenck’s American Nuclear Tailings Reclamation project is an example of reclamation with a forfeited bond. In 1994, American Nuclear Corporation filed bankruptcy and forfeited their reclamation bonds. The State of Wyoming became the licensee and was responsible to achieve adequate reclamation with limited financial resources. NRC requirements were containment for 1000 years. Over the next 15 years the State of Wyoming spent a large portion of the forfeited bond on investigations, cleanup and stabilization of Tailings Pond #2. Wenck was contracted in 2014 to complete reclamation of a 30-acre uranium mill tailing known as ANC Tailings Pond #1 (TP#1).
After three years of groundwater contamination investigations, material handling and sampling and environmental permitting, Wenck began construction oversight of the TP#1 closure in April 2018. Based on the contractor schedule, we anticipate first phase completion in late May 2018. The second phase (with Office of Surface Mining [AML] funds) will be completed in late Fall 2018 and a third phase with Department of Energy (DOE) funding is anticipated in Spring 2019. Given the limited available funding, Wenck and their partners, the State of Wyoming and the US NRC have agreed to an interim stabilization plan that eliminates windblown and waterborne dispersion of radioactive tailings for the long term, defined as no release in 200 years. Wenck completed the engineering design work to include a radon emanation cover, a wicking barrier to eliminate capillary rise of acidic water, and a cover soil surface including amended subsoil and 12 inches of topsoil. The overall cover will be 3.25 feet and the final surface will be pitted and broadcast seeded.
The Pre-Design work included sampling of several waste rock/overburden stockpiles, sampling and suitability evaluation of the material within Willow Springs Draw (Wicking Barrier) and identification, surveying and review of various topsoil stockpiles to determine their radiological and chemical suitability for use as cover material. The engineering design included the final cover design, its geomorphic stability, a detention pond and two diversion channels designed to pass the Probable Maximum Flood around the tailings pond. Following the completion of TP #1 construction, the site will meet NRC requirements for interim stabilization and minimize adverse impacts to the environment and public health and safety stabilization plan. The later phases are meant to improve on this long-term site stability.
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