The Preparation And Experimental Study Of The Spraying Material For The Tunnel Wall In Coal Mine

Gas explosion accidents occur frequently in Chinese coal mine.On the one hand,coal mine safety management has great responsibility;on the other hand,because coal mine gas emission is extremely uneven,it is difficult to detect and accurately predict.In order to ensure the safety of the coal mine underground mining process,the gas emission and operating surface,the current coal mining enterprises have basically equipped with gas monitoring system and ventilation system.The monitoring data of methane by the existing device are not accurate and reliable enough.So these data cannot be as a basis for controlling ventilation.In order to avoid the occurrence of accidents and to ensure absolute safety,monitoring data can only be used as reference data,in fact adequate ventilation caused a huge power consumption.In this paper,the concentration of gas emission from the wall of roadway is decreased and the gas emission is stabilized by using a roadway spraying material,which can provide a favorable basis for the detection of the gas concentration in the tunnel,and ensure the safe production of the coal mine.At present,the main spraying materials used in coal mines are mainly cement and organic chemicals.On the one hand,the cement materials are not very suitable for tunnel spraying of the block gas.On the other hand,organic materials are expensive and they will become economic burden for a coal mine.Therefore,in this paper,the organic inorganic spraying materials were investigated by adding the CFB ultrafine fly ash in emulsion.The main points of this paper are as follows:(1)Investigation of underground mineThrough the detailed investigation of a coal mine in Lu'an Group and found that return roadway gas concentration is the highest,and roadway wall gas emission intensity is extremely unstable,so it is not easy to detect the roadway gas concentration,which seriously affected the coal mine safety production.A detail investigation of a return roadway is made,and the details of the address structure and hydrogeology etc.are studied.(2)Experimental study on the effect of the adding amount of CFB ultrafine fly ash on roadway spraying materialsThe CFB ultrafine fly ash is used as additive to prepare gas spraying material,the apparent properties,adhesion strength,waterproof,antistatic and flame retardant properties of the spraying materials were investigated to select the best formal of spraying material.The results show that proper content of CFB ultra fly ash content is about 30%which can meet the demand.CaCl2 is selected as an activator,and the physicochemical properties of the developed coating material were investigated.The results show that the activity of CFB fly ash ultrafine are excited,and the adhesion strength of the roadway spray materials are improved,The adding amount of CFB ultrafine fly ash increase to about 40%with adding CaCl2.(3)The experimental study on the spray painting of tunnel spraying materials in the underground tunnelThe gas sealing materials developed with good adhesion,waterproof,antistatic and flame retardant function are used to spray to the coal mine underground roadway wall gas concentration is detected at the series of detection points.Through comparing the gas concentration detection data of spraying,spraying process and sprayed a week,it shows that gas concentration after spraying roadway drops 22.26%than that before spraying.The gas emission from roadway reduced to some extent.The roadway wall gas emission is relatively stable,for which it is easily to further monitor the gas concentration in mine roadways accurately,and to ensure the safety of the working face.(4)Put forward a new idea of optimization about safety production system in coral mineGas roadway surface emission affected by various factors,the emission gas concentration is very unstable and detection data of tunnel gas is not very accurate.A set of new ideas for gas detection designed in this paper.First of all,the spraying materials are used on the wall for pretreatment.The gas emission concentration is relatively stable.At the same time,a gas monitoring device wall is designed.The gas concentration monitored wind conditions.Comparing gas concentration under windless conditions and wind conditions,the gas concentrations of the current and predicted the next moment are accurately detected.That can provide useful reference basis for the underground production environment for the wind.Finally,using of fan frequency conversion technology,and ventilation control to make the required ventilation,and can ultimately play the purpose of saving energy and reducing consumption.Through the research,the CFB ultrafine fly ash is used to replace partial cement to produce tunnel spraying material.On the one hand,it is inexpensive materials for coal mining roadway gas plugging;on the other hand,the consumption of the CFB ultrafine fly ash helps to solve the accumulation of their adverse effects on the environment.Finally,it provides a new method for gas detection,improving the safety of coal mining.