Perm National Research Polytechnic University, Perm, Russia:

A. V. Nikolaev, Associate Professor, Candidate of Engineering Sciences, nikolaev0811@mail.ru

Shallow mines (to a depth of 500 m and less), for examples, mines at the Upper Kama potassium–magnesium salt deposit, face difficulties connected with heavy condensate formation in underground excavations during ventilation in warm seasons. This problem is particularly topical in salt rock mines as interaction of salt rocks with water results in generation of electrolytic solution that gives rise to wear of equipment. To prevent (reduce) moisture dropout, mine ventilation networks use mine air conditioning systems (ACS, cooling and dehydration). The application of such systems is limited as they require extremely much electric energy. This article proposes the air conditioning method, when warm air generated during cooling of air conditioner gas is “discharged” to return ventilation air flow in ventilation shaft. Condenser (air cooler) is suggested to be installed at an outlet of air supply shaft near the ventilation shaft. The condenser will pass air cooled in the air supply shaft that is far away from the ventilation shaft. As the condenser is in the underground excavation, it is sufficient to cool air in the condenser only down to temperature of surrounding rocks. In this case, secondary condensation events are eliminated, and energy consumed by the air treatment system is reduced. Owing to positive natural draft (thermal drop of ventilation pressure) and ejection effect, power consumed by ventilation system in whole is decreased. The technical-and-economic calculations have proved high energy efficiency of the proposed method.

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