The paper presents a number of mine ventilation schemes for variously located shaft collars and a main fan diffuser. The calculations of thermal drop of ventilation pressure in the inter-shaft area in each of the discussed variants involve the assessment of their effect on the mine pressure drop.Key words: natural draft, thermal drop of ventilation pressure, hydrostatic calculation method, altitude mark, diffuser, main mine fanThe natural draft or the thermal drop of ventilation pressure is an indispensable component of a mine's ventilation along with the main mine fan operation. The natural draft is generated because of the difference in air densities in mine shafts as is stated in [1,2]. The rock temperature is constant in a mine throughout a year, for example, the temperature of rocks at the Upper Kama Potassium Salt Deposit (UKPD) ranges within 7-9°С (8°С in average). Owning to the large extension of mine workings, the mine air temperature gets equal to the rock temperature, i.e., at the mine exit (in air shafts) the air temperature is also constant throughout the year. Consider the mine ventilation schematics in Fig. 1. In summer, when the outdoor temperature is above 8°С, the main mine fan supplies warm and lighter air into the air shaft ab, therefore, the cooler and heavier air is displaced from the air shaft cd. The resultant natural draft, directed from the air outlet shaft cd toward the air inlet shaft ab and toward the air flow Q; in other words, it counteracts the main mine fan operation. That natural draft is termed the "negative" draft (-h e ). Fig. 1. Mine ventilation layout.
Abstract-In the article, the options of mines aeration by means of ejector fan installation are examined, as well as the principle of this installation functioning and its potential are shown. Basing on the investigations conducted and the functioning results received, the possibility of application of the ejector fan installation as the main and auxiliary fan installation is shown. The application of the ejector fan installation as the main fan installation for aeration of the mines of the fields opened with adits or shafts of small extent on the northeast of Russia is proved. The option of using the ejector fan installation in the pit mouth as well as in underground stopings of the mine ventilating network is considered.Keywords-mine ventilating; main fan installations; ejector fan installations; underground mobile fan installation; aerodynamic drag
The author reviews alternate designs of junction of a ventilating passage and an air shaft, and alternative configurations of a ventilating passage connected to the mine main fan. Based on the aerodynamic parameters of the considered ventilating passages, the author proposes an optimized version of the cross-section and geometry of a ventilating passage, and analyzes energy costs to supply the mine main fan in the discussed variants of the ventilating passage configuration.
-The article specifies measuring data of air parameters and their volume flow in the shafts and on the surface, collected in BKPRU-2 (Berezniki potash plant and mine 2) («Uralkali» PJSC) in the normal operation mode, after shutdown of the main mine fan (MMF) and within several hours. As a result of the test it has been established that thermal drop between the mine shafts is active continuously regardless of the MMF operation mode or other draught sources. Also it has been discovered that depth of the mine shafts has no impact on thermal drop value. By the same difference of shaft elevation marks and parameters of outer air between the shafts, by their different depth, thermal drop of the same value will be active. The value of the general mine natural draft defined as an algebraic sum of thermal drop values between the shafts depends only on the difference of temperature and pressure of outer air and air in the shaft bottoms, on condition of shutdown of the air handling system (unit-heaters, air conditioning systems).
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