Dust Migration Law And Numerical Simulation In Winter In Haerwusu Open-pit Coal Mine

With the large-scale,high-efficient and centralized equipment used in open-pit coal mines in China,the production capacity of open-pit coal mines continues to increase.In recent years,the data show that the annual output of open-pit coal mine has occupied nearly 1/5 of the total output of coal in China.The efficiency,safety and flexibility of open-pit coal production determine that the proportion of total output of open-pit coal mine will further increase in the future.At present,the open-pit coal mine is an open operation.The dust and tail gas produced in each production link are directly exposed to the mine air environment.However,due to the influence of the mine structure,the air flow in the pit,especially at the bottom of the pit,is significantly reduced compared with the natural air flow,resulting in the limited blowdown capacity of the open-pit coal mine and the serious dust pollution in the pit.Haerwusu open-pit coal mine is one of the large-scale open-pit coal mines in China,which is located in Inner Mongolia Autonomous Region.Due to the lack of water resources,low water content of rocks,low rainfall,large annual output and strong mining disturbance,the dust pollution in Haerwusu open-pit coal mine is more serious than that in other areas.Dust will seriously harm human health,cause a variety of occupational diseases,shorten the service life of mining equipment,reduce the visibility of the stope in winter,and reduce the production efficiency of the mine.In this paper,based on the engineering research object of Haerwusu open-pit coal mine,the field experiment,computational fluid dynamics and fluent numerical simulation method are synthetically used to conduct a systematic and in-depth study on the dust transport law of the stope in winter.The main achievements are as follows:(1)Through theoretical analysis,combined with the actual production process characteristics of Haerwusu open-pit coal mine,the dust source distribution and the dust production mechanism of each production link are determined;the influence of inversion layer and complex circulation on the dust diffusion in the stope is discussed.(2)Combined with the field measured data,analyzed the meteorological characteristics of the winter stope,determined the structure characteristics of the inversion layer of the winter stope,revealed the change rule of dust concentration under different wind load,temperature and humidity conditions,and concluded that the dust pollution in the winter stope of Haerwusu open-pit coal mine increased first and then decreased.(3)By using fluent numerical simulation software,a three-dimensional geological model of the stope of Haerwusu open-pit coal mine is established,and the dust transport law under different wind load and dust source characteristics is studied.In winter,the distribution of complex circulation and the bottom of the stope are determined,and the dust particle size is negatively related to the escape rate,which is shown in the fact that the small particle dust is far away from the wind,and the large particle dust is mainly concentrated near the dust source.(4)Introduce the shortcomings of traditional methods of dust reduction,analyze the necessity of artificial ventilation and dust removal,and combine with the numerical simulation software,determine to adopt the diagonal arrangement of fans or the way of slotting in the waste dump for ventilation,the dust reduction effect is better.There are 70 figures,9 tables and 80 references.