Abstract: The high saturation line is a potential safety hazard for metal mines.Establishing radiation well is an effective method for decreasing the saturation line in tailings dam.The determination of saturation line location and the calculation of drainage amount are key problems when building radiation well in tailings dam.After analyzing the field saturation line data，the characteristics of saturation line under the effect of radiation well were summarized as follows:Within the range of radiant tube，the curve of saturation line is an exponential function with an inside cave.Beyond the range of radiant tube，the curve of saturation line is a logarithmic function with an outside cave.The model of saturation line and the seepage model at radiation well were deduced.The comparison between the field test and theoretical data is made and the error is analyzed.It is shown that the calculated values of saturation line and drainage amount by the model agreed well with the measured.This model can be used to predict the position of saturation line and the water drainage amount.

Key words: Tailings dam, Radiation well, Model, Saturation line, Seepage, Drainage