Author 1:
Name & Surname: Kurilko A. S.
Company: Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences (Yakutsk, Russia)
Work Position: Head of Rock Thermophysics Laboratory
Scientific Degree: Doctor of Engineering Sciences
Contacts: a.s.kurilko@igds.ysn.ru

Author 2:
Name & Surname: Khokholov Yu. A.
Company: Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences (Yakutsk, Russia)
Work Position: Principal Researcher
Scientific Degree: Doctor of Engineering Sciences

Author 3:
Name & Surname: Soloviev D. E.
Company: Institute of Mining of the North, Siberian Branch, Russian Academy of Sciences (Yakutsk, Russia)
Work Position: Senior Researcher
Scientific Degree: Candidate of Engineering Sciences

The article characterizes mining and formation of temperature conditions in year-round and seasonal placer mines (PM) in permafrost zones. The key requirement of the temperature condition control in PM in permafrost zones in summer is prevention of thawing of the enclosing frozen particulate rock mass. The use of self-propelled diesel machines in such mines allows essential rise in labor efficiency and, thus, cut down in cost of placer mining. At the same time, the mine air impurity with exhaust gases grows, which calls for continuous enhanced ventilation of PM. The authors present a prognostic estimate (based on mathematical modeling) of temperature conditions in air inlet roadways and stopes, as well as in enclosing rock mass in terms of Solur placer mine under planning. According to the calculations, during winter operation of Solur PM with the uncontrolled temperature conditions (without artificial heating or cooling of mine air), enclosing rocks will increasingly cool and accumulate cold air. This will ensure stability of mine workings and safety of mine personnel. At the same time, low temperature in stopes (in the coldest period, it can be –5 to –19 ^оС) may cause frigorism and increased common cold rate, which respectively results in decline in PM output. In summer time (in year-round PM), when air heat comes in mine together with ventilation air flow, enclosing rocks will rapidly thaw (thawing areas in enclosing rocks of air inlet roadways may reach 1.6 m in size by the end of the summer period), which will make them unstable and require escalation of cost for enclosing rock mass support and heat-insulation. It has been concluded that from these viewpoints, it is preferred to carry out placer mining seasonally (in winter period only). Accordingly, the authors determine the optimized dates for placer mining suspension in summer. It is quantitatively evaluated how heat emission of self-propelled mining machines influences temperature conditions in stopes and enclosing rock mass.

The authors appreciate participation of V. V. Kiselev, Senior Researcher, Candidate of Engineering Sciences, Institute of Mining of the North SB RAS, in this research.

1. Tekhnologicheskiy reglament na podzemnuyu otrabotku mestorozhdeniya “Solur” (Technological regulations on underground mining of “Solur” deposit). Moscow : Institute of Comprehensive Exploitation of Mineral Resources of Russian Academy of Sciences, 2013. (in Russian).
2. Khokholov Yu. A., Solovev D. E. Prognoz teplovogo rezhima rudnika s uchetom dinamiki razvitiya gornykh rabot (Forecast of thermal mode of mine taking into account the mining development dynamics). Gornyy Informatsionno-Analiticheskiy Byulleten = Mining Informational and Analytical Byulletin. 2009. No. 5. pp. 270–275.
3. Emelyanov V. I., Mamaev Yu. A., Kudlay E. D. Podzemnaya razrabotka mnogoletnemerzlykh rossypey (Underground development of permafrost placers). Under the editorship of V. I. Emelyanov. Moscow : Nedra, 1982. 240 p.
4. Available at: base.garant.ru/70691622/ (accessed: March 27, 2015). (in Russian).
5. Sherstov V. A. Podzemnaya razrabotka mnogoletnemerzlykh rossypnykh mestorozhdeniy : uchebno-metodicheskoe posobie (Underground development of permafrost placer deposits : tutorial). Yakutsk : Yakutsk State University, Institute of Mining of North of Russian Academy of Sciences, 2002. 124 p.