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

Authors: Khokholov Yu. A.

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.

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.

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