Study On Dust Initiation Mechanism And Prevention Strategy In Non-disturbed Area Of Open-pit Mine

The dust pollution of open-pit mining presents the characteristics of "many points,wide range and high pollution concentration".The dust pollution of open-pit mines has become a prominent social problem.Most of the dust in the operation link of open-pit mining is mechanical dust,and most of the dust is the primary dust source with large particle size near the mechanical equipment in the operation link.The open-pit mine is an open space with large exposed area.According to the analysis of operation distribution area,most areas in the open-pit mine stope are not the main operation space,and are not subject to mechanical disturbance or the frequency and degree of mechanical disturbance are very small,which can be considered as non-human disturbance areas.There is no disturbed dust generation in the non disturbed area.The dust particle size is small,the suspension time in the atmosphere is longer,the diffusion distance is longer under the action of wind load,and the influence range is larger.It is the main diffusion source of dust in the mine pit.Therefore,it is necessary to comprehensively control the dust in the non-disturbed area.This thesis takes the comprehensive prevention and control of dust in open-pit mine as the research background,and carries out the regional division of dust pollution according to the operation characteristics of open-pit mine.It mainly studies the dust initiation mechanism and diffusion law of dust in the non-disturbed area of open-pit mine.Combined with the dust initiation characteristics and micro morphology of dust in the non-disturbed area,it develops the adhesive dust inhibitor,puts forward the comprehensive prevention and control strategy for dust in the non disturbed area of open-pit mine,and puts forward the on-site construction technology of dust inhibitor in the non-disturbed area,And carry out field engineering application.The main research work of this thesis is as follows:(1)According to the disturbance intensity of dust factors in different links and areas of open-pit mine,the concepts and dust characteristics of dust disturbance area and non disturbance area of open-pit mine are put forward,the distribution area of non disturbance area is defined,and the idea of sub regional treatment of open-pit mine dust and the dust treatment method of non disturbance area are put forward.The dust in the non-disturbed area of open-pit mine is pneumatic dust,and the main influencing factors are wind speed and wind force.(2)The dust in the disturbed area of open-pit mine is the primary dust source and the main source of dust.The particle size distribution of dust is relatively uniform,and the proportion of d10,D50 and D90 is similar.The dust in the non-disturbed area is mainly the secondary dust source,and D10 accounts for the largest proportion in the dust particle size,and the particle size is smaller.The micro surface of dust in the nondisturbed area is rough,showing irregular and disorderly distribution of pores and obvious agglomeration.(3)The dust generation method in the non-disturbed area of the open pit mine is wind borne dust generation.The maximum escape and capture time of dust diffusion in the non-disturbed area of the waste dump decreases with the increase of wind speed.The dust diffusion path is similar to the wind flow path,and there is little horizontal diffusion in the windy state.PM100 can be blown up by the wind and migrate in the mining area when the wind speed is 5m / s,and the maximum diffusion range is 100 m.Non-disturbed area of waste dump PM2 5.The escape rate is higher than PM10 and PM10 is higher than PM100.With the increase of wind speed,the dust diffusion time gradually decreases,and the dust diffusion time in the middle is the longest.(4)Combined with the dust characteristics,dust characteristics and environmental conditions in the non-disturbed area,a bonded dust inhibitor is developed.The dust inhibitor is pre-gelatinized starch as the main material and mixed with thickener nonionic polyacrylamide.The dust inhibitor with 1.0% concentration,i.e.0.9% pregelatinized starch and 0.09% thickener,is selected as the ratio.The dust suppression principle of adhesive dust suppressor in non-disturbed area is as follows: adhesive dust suppressor will form a layer of adhesive film on the surface of dust particles,increase the adhesion and clustering between dust particles,and increase the ability to resist wind disturbance.(5)The dust suppression test of adhesive dust inhibitor in non-disturbed area was carried out in harwusu open pit coal mine,and the on-site preparation process and construction technology of dust inhibitor in non disturbed area were put forward.The on-site dust suppression tests in non-disturbed area of waste dump,exposed coal pile and weakly disturbed road were carried out respectively.The dust suppression effect in the test area was good,The concentration of PM10 and PM2.5 particles and TSP decreased significantly.There are 127 figures,28 tables and 114 references in this thesis.