The US Department of Energy (DOE) is conducting cleanup activities at the Weldon Spring site, which is located in St. Charles County, Missouri, about 48 km (30 mi) west of St. Louis. The Weldon Spring site consists of two noncontiguous areas -- the chemical plant area, which includes four raffinate pits, and the quarry. Cleanup activities at the Weldon Spring site are conducted in accordance with the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), as amended, incorporating the values of the National Environmental Policy Act (NEPA). The contents of the documents prepared for the project are not intended to represent a statement regarding the legal applicability of NEPA to remedial actions conducted under CERCLA. In accordance with the integrated CERCLA/NEPA approach, a remedial investigation/feasibility study-environmental assessment (RI/FS-EA) is being conducted to evaluate conditions and potential responses for the quarry residuals operable unit (QROU). This operable unit consists of the following areas and/or media: the residual material remaining at the Weldon Spring quarry after removal of the pond water and bulk waste; underlying groundwater; and other media located in the surrounding vicinity of the quarry, including adjacent soil, surface water, and sediment in Femme Osage Slough. This work plan identifies the activities within the RI/FS-EA process that are being proposed to address contamination remaining at the quarry area.