Research On Ventilation System Of Metal Mine At High Altitude

Mine ventilation ensures the safety in production of underground mine to a large extent. In high-altitude areas, the air density, the oxygen content and other parameters decrease with the increasing altitude. So compared to plain areas, a number of special requirements should be considered in mine ventilation system of high-altitude areas. This study is carried out on the background of "Twelfth Five Year" National Science and Technology Support Program and the project is entitled as "Research on the mining security technology at high altitude in Tibet (Project No.2012BAB01B04)". Based on the review and analysis of relevant literature and research results at home and abroad, the corresponding theoretical research was conducted on the ventilation system of metal mine at high altitude, using methods of field measurement, comparative analysis, theory study and numerical simulation. The main content of this paper is as follows:(1) The variation characteristics of the climatic in mining district were analyzed and the extent of hypoxia in high altitude environment for miners was determined. According to the measurement for relevant parameters of the ventilation system comprehensively, the existing ventilation problems were pointed out. Then characteristic curve polynomial for the ventilator was derived using the least square curve fitting technique. And compared with the standard conditions, the plateau drop effect ratio of the ventilator was determined. The ventilation resistance was measured by the barometer method and the difficulty of mine ventilation was evaluated. The variations of the natural wind pressure all the year round and in a day of winter and summer were calculated and the influence of natural wind pressure on mine ventilation was analyzed. At last the construction principles for the whole mine ventilation system were put forward based on the above analysis.(2)The basic physiological indicators in different periods for miners from plain areas to the altitude of4000m were tested in order to study the hypobaric hypoxia underground work environment in plateau areas. And the miners’altitude acclimatization adaptation state was analyzed using SPSS software. Then the corresponding formula of altitude, oxygen saturation and labor load was established through research of human endurance physiological indices. And the study shows that after acclimatization the degree of adaptation to hypoxia of miners can reduce accordingly. Then the target coefficient of oxygen and pressurized was determined accordingly, which provided reference for improving the working environment of underground hypobaric hypoxia.(3) In order to relieve the hypoxia problem for underground miners at high altitude and improve labor productivity, the necessity and feasibility of partial pressurization were analyzed in the local stope theoretically and a partial pressurization test model were analyzed. Then this paper researched the influence of the ventilation pressure, the positive resistance and the ventilation air flow on the average pressure, the wind velocity or volume of each branch in supercharging pressure areas through single factor test and positive cross experiment. And finally the quantitative pressurization effect in local stope was obtained through regression analysis.(4) The construction scale of the mine, the develop engineering and mining methods were analyzed comprehensively and the entire ventilation system project was divided into three relatively independent ventilation units. Then the optimal regulation technology of controlled air distribution network was analyzed. And the concept that "working face is the service core" was presented. And the Combined control approach of "pressure-based, suction and pressure multi-stage ventilator station+unit ventilation+partial pressurization" was adopted. Then the construction plan of the ventilation system of large underground metal mine in high-altitude areas was proposed. At the same time, the theoretical air volume required by the entire ventilation system was calculated.(5) Based on the system construction and ventilation network adjustment program, this paper identified the key branches for stability analysis of the mine ventilation system. Using the VENTSIM software, this paper did a lot of simulation resolving. Then the influence of branch wind resistance change with the air flow on the key segments in the inlet section, wind section and the return air section was analyzed quantitatively. At the same time, the corresponding countermeasure was given. Finally according to the above findings and the given node and the adjustment measures, a system-wide optimization adjustment and the ventilation network simulation results analysis were launched.The research was closely linked to the production reality of high-altitude mines and provided strong technical support for the ventilation system construction of JiaMa polymetallic mine.