The paper describes a solution to the problem of maintain the stability of a fill slope through artificial freezing with seasonal cooling units in cryolithozone. A three-dimensional mathematical model was developed to calculate the heat flow in a fill slope reinfirced with a gabion wall, taking into account the liquid-liquid phase transition and the use of seasonally operating cooling units. The developed mathematical model, based on the finite difference method and implemented as an application for Microsoft Windows, allows making a long-term forecast of a temperature field in a fill slope, depending on various design and technological parameters (location, dimensions and an operating mode of thermal stabilizers) and its effect on the stability of the slope. The results of studying the contribution of thermal stabilization to a reduced destructive temperature effect of the environment on the slope are given. The study showed the effectiveness of using seasonal cooling units for increasing the stability of fill slopes by freezing. In subsequent years after the thermal stabilization, the frozen zone in the fill slope is preserved, with the slope gradually switching to the natural seasonal temperature regime. The paper is recommended for researchers and designing engineers dealing with applied issues of mining thermal physics.