Abstract
<jats:p>The article outlines negative factors that make mining of underground kimberlite deposits in the cryolithozone more complicated. It describes the proposed methods, i.e. construction of an ice rock block at the bottom of a depleted kimberlite open pit, freezing of ice rock mass using waters of a man-made lake, and construction of a single-layer and double-layer thermal insulation screen. The results of calculations using the authors' methodology for the temperature regime of the ice rock mass and the thermal insulation screen at different thicknesses of the rock backfill and polystyrene layer are presented in graphical form, making it possible to assess the dynamics of the thermal processes occurring throughout the year, which confirm the efficiency of the double-layer thermal insulation structure. It is emphasized that implementation of the proposed method makes it possible to ensure the frozen state of the constructed block if a waterproof coating and a functioning drainage system is in place; the safety of mining operations in the underground mine that is used to develop the pit reserves; the stability of the near-wall rock mass of the worked-out open pit; development of the existing ore body with additional revenue.</jats:p>