Features of heat- and mass-exchange in a safety cushion in mining under open pit bottom

Authors: Хохолов Ю. А.

The article presents the mathematical model data and features of heatand mass-exchange processes in a safety cushion filled on the bottom of an open pit. These features govern mobility and permeability of the cushion during mining of kimberlite pipe reserves under the pit bottom using the systems with caving. The temperature and moisture content (ice content) distributions in depth of the safety cushion are given for different values of the depression (pressure difference) at the upper and lower boundaries of the cushion in the conditions of upward flow of warm mine air. The critical role of the heatand mass-exchange processes and their control towards the safety cushion stability is emphasized. For different thicknesses of the safety cushion, the depression values required to eliminate ice accumulation in voids are calculated. It is stated that one of the methods to stabilize mobility and permeability of the safety cushion under negative temperatures of the ambient medium and rocks can be its artificial salinification with natural subpermafrost highsalt water. The calculated examples of air depression at different temperatures of phase transitions of water and at various thickness of the safety cushion are presented.

Keywords: Underground mining, mined-out open pit, safety cushion, permafrost zone, phase transitions of water, ice content, temperature, depression.
For citation:

Khokholov Yu. A. Features of heatand mass-exchange in a safety cushion in mining under open pit bottom. MIAB. Mining Inf. Anal. Bull. 2020;(2):13-21. [In Russ]. DOI: 10.25018/02361493-2020-2-0-13-21.

Acknowledgements:
Issue number: 2
Year: 2020
Page number: 13-21
ISBN: 0236-1493
UDK: 622.272 (571.56)
DOI: 10.25018/0236-1493-2020-2-0-13-21
Article receipt date: 01.11.2019
Date of review receipt: 18.11.2019
Date of the editorial board′s decision on the article′s publishing: 20.01.2020
About authors:

Khokholov Yu. A., Dr. Sci. (Eng.), Leading Researcher,
e-mail: khokholov@igds.ysn.ru,
Chersky Mining Institute of the North, Siberian Branch, Russian Academy of Sciences, 677018, Yakutsk, Republic of Sakha (Yakutia), Russia.

For contacts:
Bibliography:

1. Kolganov V. F., Akishev A. N., Drozdov A. V. Gorno-geologicheskie osobennosti korennykh mestorozhdeniy almazov Yakutii [Mining and geological features of radical deposits of diamonds in Yakutia], Mirnyy, Mirninskaya gorodskaya tipografiya, 2013, 568 p.
2. Sokolov I. V., Smirnov A. A., Antipin Yu. G., Kul'minskiy A. S. Development of sub-quarry reserves of the Udachnaya pipe in difficult climatic, mountain, and hydrogeological conditions. Gornyy zhurnal. 2011, no 1, pp. 63—66.
3. Sokolov I.V., Smirnov A.A., Antipin Yu.G., Nikitin I.V., Tishkov M.V. Justification of the thickness of the safety cushion when working out the quarry reserves of the Udachnaya pipe with collapse systems. Fiziko-tekhnicheskiye problemy razrabotki poleznykh iskopayemykh. 2018, no 2, pp. 52—62.
4. Shubin G. V., Zarovnyaev B. N., Kurilko A. S., Dmitriev A. A. Tekhnologicheskie svoystva rud i vmeshchayushchikh porod Udachninskogo mestorozhdeniya [Technological properties of ores and host rocks of the Udachninsky deposit], Novosibirsk, Nauka, 2017, 160 p.
5. Kovalenko A. A., Tishkov M. V. Evaluation of the Udachnaya pipe deposit underground mining using caving system. Gornyy informatsionno-analiticheskiy byulleten’. 2017, no 4, pp. 117—128.
6. Kurylyk B. L., MacQuarrie K. T. B., McKenzie J. M. Climate change impacts on groundwater and soil temperatures in cold and temperate regions: implications, mathematical theory, and emerging simulation tools. Earth-Science Reviews, 2014, vol. 138, pp. 313—334. DOI: 10.1016/j. earscirev.2014.06.006.
7. Karra S., Painters S. L., Lichtner P. С. Three-phase numerical model for subsurface hydrology in permafrost-affected regions (PROTRAN-ICE v.1.O). The Cryosphere. 2014, vol. 8, pp. 1935— 1950. DOI: 10.5194/tc-8-1935-2014.
8. Wu M., Jansson P.-E., Tan X., Wu J., Huang J. Constraining parameter uncertainty in simulations of water and heat dynamics in seasonally frozen soil using limited observed data. Water. 2016, vol. 8(2), pp. 64. DOI: 10.3390/w8020064.
9. Sjöberg Y., Coon E., Sannel A. B. K., Pannetier R., Harp D., Frampton A., Painter S. L., Lyon S. W. Thermal effects of groundwater flow through subarctic fens: a case study based on field observations and numerical modeling. Water Resources Research. 2016, vol. 52, no 3, pp. 1591—1603. DOI: 10.1002/2015WR017571.
10. Painter S. L. Three-phase numerical model of water migration in partially frozen geological media: model formulation, validation, and applications. Computational Geosciences. 2011, vol. 15, pp. 69—85.
11. Zhou Y., Zhou G. Numerical simulation of coupled heat-fluid transport in freezing soils using finite volume method. Heat and Mass Transfer. 2010, vol. 46, no 8, pp. 989—998. DOI: 10.1007/s00231-010-0642-2.
12. Golubev V. N., Frolov D. M. Peculiarities of water vapor migration at the atmosphere —snow cover and snow cover —underlying soil interface. Kriosfera Zemli. 2015. Vol. XIX, no 1, pp. 22—29.
13. Zarovnyaev B. N., Shubin G. V., Kurilko A. S., Khokholov Yu. A. Forecast of the temperature and humidity state of the safety cushion during mining of quarry ore reserves in the permafrost zone. Gornyy zhurnal. 2016, no 9, pp. 33—36.
14. Neustroev A. P., Khokholov Yu. A. Influence of atmospheric precipitation infiltration on the temperature and humidity regime of the rock pillow under the conditions of the North. Gornyy informatsionno-analiticheskiy byulleten’. 2017, Special edition 24, pp. 310—318.
15. Neustroev A. P., Khokholov Yu. A. Ice accumulation in rock safety cushion, considering atmospheric precipitation seepage and moist mine air leak in the conditions of permafrost region. Gornyy informatsionno-analiticheskiy byulleten’. 2018, no 12, pp. 39—47. DOI: 10.25018/02361493-2018-12-0-39-47. [In Russ].

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