Abstract:

With the extension of mining to the deep，the harsh mining environment of “three high and one flexible” is becoming increasingly prominent，among which the high temperature thermal hazard is a complex problem.In the process of mine production，under the influence of high temperature and heat environment，the air flow in mine roadway exchanges moisture and heat in high temperature and heat environment，which makes the air flow temperature rise，and then induces a series of problems，which eventually lead to a series of problems，such as difficulty in ventilation management，decline of production capacity，deterioration of working environment and so on.Because of the large depth of the mine，it is more difficult to ventilate and cool down the mine.During the period of mine ventilation，air flow is discharged from the surface along the shaft，roadway to the working face and through the return air shaft.During the above process，the air flow exchanges greatly with the mine environment in the shaft，roadway and working face，and the nature of air flow changes accordingly. Exploring the temperature variation characteristics of air flow in three stages of shaft，roadway and working face is helpful to determine the appropriate mining depth and choose the appropriate cooling mode. For deep mines，it is difficult to meet the need of deep mining only by using ventilation cooling technology.Reveal romantic from the perspective of thermodynamics in the heat exchange law ventilation circuit principle of finite difference method was used to calculate deep wellbore temperature，and in this roadway and the working temperature change trend was deduced，combined with the mine safety production permit back-stepping，temperature eventually acquire ventilation cooling recoverable under the condition of the limit depth formula.Guangxi copper mine zinc polymetallic ore body was sellected as engineering application test area，to analyzed the formula.The results show that the heat exchange model based on airflow can deduce the calculation formula of airflow temperature in wellbore，roadway and working face.Assuming that the working face temperature reaches the maximum allowable temperature for safe mining，the mining limit depth and the ventilation limit length of the roadway under this condition can be deduced reversely （when ventilation and cooling measures are adopted only）.Based on the actual conditions of the zinc polymetallic ore in the Tong-keng mining area，relevant data are brought in to verify that the calculated limit mining depth is in line with the reality，that is，the derived formula is feasible.

Key words: high temperature deep well, high temperature heat damage, ventilation and cooling, principle of difference method, wind temperature prediction, limit depth of mining