8 AUGUST 2025 WorldWide Drilling Resource® Rifle Disposal Cell Pore Water Extraction Project Adapted from Information by the Department of Energy (DOE) When the DOE Office of Legacy Management (LM) encountered an operational hurdle at the Rifle Disposal Site in Colorado, near Rifle, a team of specialists from various fields came together to find a solution. Established in 1996, the 71acre disposal cell, near the City of Rifle, was designed to safely store uranium mill components and mill tailings from two former uranium and vanadium processing facilities, known as Old Rifle and New Rifle. In 2001, water began to accumulate within the disposal cell, necessitating its transfer to a nearby lined evaporation pond. However, as the years went by and the system aged, the environmental measures in place struggled to manage the increasing water levels, which posed a risk to the structural integrity of the site. Consequently, in 2024, LM made it a priority to design and implement a new system of strategically located, solar-powered extraction wells and evaporation ponds to effectively resolve the situation. Before work commenced at the site, the team had to navigate a range of challenges, including environmental compliance issues related to the removal of radiological waste, water rights consideration, and necessary project permits. To determine the optimal number and placement of new extraction wells, LM undertook an in-depth review of the disposal cell’s construction and the ongoing water accumulation. To ensure safe drilling without disturbing buried mill materials, hydrogeologists relied on a geophysical survey to identify the best locations for the new wells. The project team initiated drilling operations on the disposal cell itself. To protect the existing riprap cover, workers constructed a temporary road using interlocking, heavy-duty construction mats. Once the path was established, LM deployed a drill rig and other necessary equipment. As drilling progressed, the temporary paths were adjusted to suit each drilling site, ensuring safe and stable surfaces for the crew. Throughout the drilling operations, Legacy Management Support Partners (LMSPs) implemented a LIDAR (Light Detection and Ranging) system to scan the disposal cell, addressing concerns about maintaining the integrity of the cell during the drilling process. Using the LIDAR system, LM was able to verify there was no movement of the disposal cell during the operations carried out by the equipment and staff. With all preparations finalized, drilling commenced, aiming to add ten new extraction wells, bringing the total to 12 wells actively extracting water from the cell. In addition, four monitoring wells were drilled to track the water levels within the cell. While the main drilling activities were underway, another team focused on constructing the modular evaporation ponds. The establishment of these new wells and infrastructure necessitated an increase in power supply for the system to function effectively. After the drilling on the disposal cell was completed, a new solar power system alongside the System Operation and Analysis at Remote Sites (SOARS) were installed to meet the energy requirements. The SOARS system enables LM to manage and monitor the new water extraction system remotely. Once the components of the SOARS systems were assembled and the pipeline connecting the wells to the modular evaporative ponds were in place, tests were conducted to measure the extraction rates of pore water - the water that seeps into the tiny spaces between soil and sand grains. As the volume of water removal increased, it became clear there was a need for enhanced evaporation capacity to handle the additional load. The construction and engineering teams collaborated effectively to finalize the design for the two modular evaporative ponds. Meanwhile, the procurement team played a crucial role in efficiently acquiring the necessary equipment and addressing supply challenges as they emerged. With maintenance efforts for the disposal cell concluded, it was time to restore the surrounding land to its original condition prior to the start of work. Workers began by scoring the soil to facilitate growth of native plants. With all tasks on-site now finished, the wells are functioning as intended, successfully extracting the pore water needed to maintain the integrity of the cell. Ongoing site monitoring will be conducted using data collected and transmitted by the SOARS stations, ensuring compliance with long-term surveillance plans to safeguard human health and the environment. Project contractors and LMSP staff install a well based on design strategy developed by LMSP Senior Hydrogeologist Pete Schillig. LMSP Survey Technician Josh Helmick demonstrates how to set up the LIDAR scan while LM Team Lead Wil Burns and LM Site Manager Sara Woods listen. WTR
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