Uranium (U) release from mining has been typically associated with former U mine sites, but trace U levels in iron or base metal ores can also lead to U mobilization into ground and surface water posing potential risks due to U's chemical toxicity and radioactivity. This study investigates U sources and mobility at an iron ore mine site in Northern Sweden, where U concentrations (median 1.8 μg/l) exceeding the Swedish annual guideline value of 0.17 μg/l have been detected in a river receiving excess process water from the mine site. Drill core samples were characterized to identify the minerals hosting U in the iron ore and sequential extraction tests were conducted on solid samples from the processing plant to assess U mobility potential. Results indicate that, given its low U content, iron ore is not a significant source of the elevated U levels detected in the process water. Thorite, the main U-bearing mineral remains stable under the neutral to alkaline pH conditions in the processing plant. U speciation calculations on process water monitoring data, performed in PHREEQC with the PRODATA thermodynamic database, revealed dominant calcium uranyl carbonate complexes, specifically Ca