Abstract

Aquifer characterization is one of the required steps in developing an area for in-situ leaching of uranium. Characterization is usually accomplished by using multiple disciplines to gain an overall understanding of the aquifer. This paper focuses on one aspect of characterization typically used in the ISL industry: the pumping test. The pumping test is conducted to determine aquifer formation properties such as transmissivity, hydraulic conductivity, permeability, anisotropy and storage. It also may yield information such as vertical permeability for the adjacent confining units. This information is used to establish monitor well locations and estimate operational factors such as producing well pump rates which will influence the infrastructure design. The case history discussed in this paper is the H-Wellfield area of the Highland Uranium Project in the Powder River Basin of Wyoming. The uranium mineralization is located in the Fort Union Formation which is the aquifer being characterized.