History and current situation of mine water treatment in Ningyo-toge Uranium Mine

Nagayasu, Takaaki ; Taki, Tomihiro; Fukushima, Shigeru 

The forerunner of JAEA, found a smelter in 1964 to do industrialization tests of hydrometallurgical extraction process from domestic uranium ore to uranium tetrafluoride, extracted at Ningyo-toge. Yotsugi Mill Tailings Pond was constructed for the purpose of depositing slag and other things generated due to the operation of the smelter. Furthermore supernatant water from the deposition field had been treated appropriately at wastewater treatment facilities, which has been provided in the downstream site of the pond. We have been utilizing the Yotsugi Mill Tailings Pond as a temporary storage field of mine water generated from the old mining gallery, mainly. After filing an abolition report of facilities of the smelter, with the completion of industrial trials of refinery in 1982. Ningyo-toge environmental engineering center has studied for processing uranium and radium, in wastewater, which must be reduced more safely by advancing these processing technical development. Supernatant water of The Pond is treated at the wastewater treatment facilities before discharging to Ikegogawa-river. And those collateralize the emission standards to discharge to the river set at the Center with continuing stable processing. This document summarized the history of the wastewater treatment, technical development for the water treatment, and the current situation of the water treatment.