Study On The Dust Migration In Fully Mechanized Mining Face And The Comprehensive Dust Removal Technology

With the progress of tunneling technology,dust discharge of fully mechanized mining face increases significantly.While A lot of mines of Yankuang group under the condition of no dust prevention measures,it turns out the dust concentration of fully mechanized mining face reaching 500~1000 mg/m3,beyond the standard of?The Coal Mine Safety Rules ?.Not only dust can destroy the equipment working environment,accelerate wear and tear of the mechanical,reduce the visibility of workers,increase the risk of accidents,But also a big threat to the worker's health.Especially the increase in respiratory dust concentration makes more pneumoconiosis occurrence.Therefore,we must take effective methods to lowering dust concentration of the working face.Three methods(field observations,theoretical analysis,numerical simulation)are applied to study the dust migration of working face.At first,measuring the dust of concentration Dongtan mine 1307 working face,then analyzing its dispersion and particle properties,etc.Furthermore,using k-e model which is based on gas-solid two-phase flow theory to describe dust migration with software Fluent,Dust migration regularity are described combining Wind flow field with Dust concentration.At last,dust removal craft parameters of far-pressing-near-absorption are obtained by simulation technology.In this paper,Comprehensive dust removal system is comprised by roadheader high pressure mist spray dust removal system and controllably large air volume far-pressing-near-absorption dust removal system.Mist spray dust removal system has a G pressure nozzle with 12 Mpa sprayer pressure,Dust removal craft parameters of second dust removal system is just same as result of numerical simulation.Then taking the Comprehensive dust removal system into to engineering to find out how it works.This paper comes out with following conclusions:(1)Most dust particle size of Dongtan mine 1307 working face is distributed in0~50 mm,dust particle size which is less than 50 mm reaches 98.8% of the total.It shows small sized particle dust makes the big part of the dust in Dongtan mine 1307 working face which means more danger to workers.(2)The numerical simulation of dust migration regularity indicates: high dustconcentration area is concentrated in the range of 10 m away from the working face,the highest dust concentration can reach up to 1500 mg/m3,and with the increase of distance from the working face,the dust concentration gradually decreases;dust concentration of the area close to the floor is more heavy than the area which far away from the flow,so does the diffusion action.dust concentration in the side of absorption tube is more heavy than side of pressing tube.In fact,the highest dust concentration position is not near the working face but in the 5m from the working face.Throughout the whole mine,dust migration achieve stability after 30 m and the dust concentration remain in 80 mg/m3.(3)According to the result of Dust removal craft parameters numerical simulation,it turns out while the pressing volume 280m3/min,pressing tube 16 m and absorption tube4 m from working face,extraction pressure ratio stay 1.4,dust concentration in mine remains a very low level.(4)Engineering of Comprehensive dust removal system shows: The dust removal efficiency of Total dust and respiratory dust catch up to 96%.Total dust and respiratory dust in 1# position stays in 7.5mg/m3 and 4.7mg/m3,the 2# position stays in 2.2mg/m3 and 2.0mg/m3.Working environment in fully mechanized mining face are improved greatly.