Thawing of rocks in shaft sinking with artificial ground freezing

The article describes the experimental data on frozen walls of mine shafts under construction in two underground mines operating in Starobin and Upper Kama potassium salt deposits. On the evidence of the experimental data, the temperature dynamics in rock mass is analyzed in different periods of evolution of frozen walls around the shafts. For the temperature balance assessment in rock mass, the amount of heat output and input in rocks in certain freeze and thaw periods is calculated. In view of the experience gained in sinking of mine shafts with artificial ground freezing, the choice of the rock mass thawing method is mostly governed by the actual construction plan of a specific mine. Using the calibrated models of thermodynamics in rock mass areas subjected to freezing, a series of numerical calculations of heat distribution is performed with a view to enhancing safety and efficiency of vertical shaft sinking. The multivariate modeling results made it possible to identify the most efficient methods to thaw rocks with regard to their preliminary freezing conditions and with respect to the current plan of construction of mining and processing infrastructure. It is found that with the artificial ground freezing method, duration of the temperature stabilization period in frozen rocks to reach the state of natural geothermy (at a bias not more than by ± 2 °С) is longer than the entire construction period of mine shafts.

Parshakov O. S., Levin L. Yu., Semin M. A. Thawing of rocks in shaft sinking with artificial ground freezing. MIAB. Mining Inf. Anal. Bull. 2021;(8):51-69. [In Russ]. DOI: 10.25018/0236_1493_2021_8_0_51.

The studies were supported by the Russian Science Foundation, Project No. 19-77-30008.

O.S. Parshakov¹, Junior Researcher, e-mail: olegparshakov@gmail.com,
L.Yu. Levin¹, Dr. Sci. (Eng.), Head of Aerology and Thermophysics Department, e-mail: aerolog.lev@gmail.com,
M.A. Semin¹, Cand. Sci. (Eng.), Researcher, e-mail: mishkasemin@gmail.com,
¹ Mining Institute of Ural Branch, Russian Academy of Sciences, 614007, Perm, Russia.

O.S. Parshakov, e-mail: olegparshakov@gmail.com.

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