【正文】 rosity, thermal conductivity, is the spontaneous bustion of coal. Oxidation of coal at room temperature mainly depends on the volatile content, the higher the 3 volatile content, the stronger the tendency of spontaneous bustion, spontaneous bustion time will be shortened accordingly. According to the relationship between the degree of oxidation and ignition point of coal, raw coal sample ignition point and oxidized coal samples of the ignition point of difference ΔT to speculate that the spontaneous bustion tendency of coal. In general, coallike fire below and ΔT large easy to spontaneous bustion of coal。 the other is the use of some of the gas position changes in characteristics (growth rate) or some gas group variation (ratio) between the points predicted to fall into this category, such as alkanes, fire coefficient and so on. The two types of forecasting methods, the most widely used is the latter. The gas analysis method of means of monitoring has detection tubes, gas sensors, portable instrumentation, and chromatographic analyzer. Detection pipe lagging behind because of its means of operation, the determination of results of operations and the degree of automation is low, can not be achieved automatically monitors are gradually eliminated by a number of coal mines。 αStephen Boltzmann constant, (1012cm2)K4。 C and baking time is short, the overlying rock or coal seam can not form magic high。 bined with underground stray current for the detection of underground hightemperature region is more difficult at home and abroad for openpit mining and spontaneous bustion in the detection of coal seam outcrops. Tracer gas method SF16, 1211, such as good thermal stability of the tracer gas for the determination of the amount of Gob has been successful. According to the experience in the application of this technology, you can choose some easy under the conditions of a temperature pyrolysis gas release in the same environment with these trace gases, the sampling point sampling to detect changes in proportion, or determination of the relevant deposition, thus indirectly, to understand the value of the temperature of the coal seam fire hazards point to achieve the forecast purpose. The choice of tracer substances have a significant impact on the determination of coal thermal regime. According to the actual environment of the mine, the tracer of choice should follow the following principles: ① toxicity。 ⑤ The deposition is easily detected。 bee the partial oxidation of coal seam after spontaneous bustion or plete oxidation of coal, its position changed dramatically, causing the apparent change in the electrical properties and, therefore, easy to distinguish between the burning of coal, partial oxidation of coal and raw coal [2]. Microwave technology for fire detection Microwaves are electromagic waves of a wavelength between 1 mm and 187 mm. The study found that the microwave radiation for any material outside of the metal has good peration, and less susceptible to the effects of smoke and vapor. 16 In view of the microwave has many inparable advantages pared to infrared, microwave technology used in modern fire detection will be a good choice. 4 Measures to prevent the spontaneous bustion of coal Prevent the coals to spontaneous bustion bining prevention with control, to prevent the main. Analyze the reasons for the spontaneous bustion of coal, put forward the following measures: (1) Coal spontaneous bustion tendency of identification, to master the law of the spontaneous bustion of coal fires in a targeted manner to take fire prevention measures to ensure the safe production of great significance. Therefore, storage of the spontaneous bustion tendency of large coal fields of coal and coal storage a long time, should be made of coal spontaneous bustion tendency of identification, determination of coal volatile content, the minimum ignition temperature, spontaneous bustion period and other indicators. (2) Coal Storage and piling methods should be selected to maintain a wellventilated to prevent the coal pile exposure. It would be appropriate to Coal Storage set in a spacious area, the back of a sunny place (such as the northern slope of the high mountains), or set up a coal shed. Around the lower part of the coal yard shall have a high temperature heat source. This can reduce the oxidation rate of coal. (3) To correctly verify the coal storage time and no more than the coal spontaneous bustion period. Open coal storage case, storage of coal for too long to ignite one of the main reasons. Moreover, the coal storage time is longer the higher the degree of oxidation, the economic value of coal fell more and more. (4) The coal layer by layer with a bulldozer paction, especially the side you 17 want to heap chunk part of the pacted blanket layer of clay better, thus reducing the porosity of the coals of, get rid of the coal pile gap air, reducing the contact of coal with oxygen. Bedding clay will increase the ash content of coal and did not accord with the coal requiring a higher NA. Spraying condensate material, the surface of the coals can prevent outside air infiltration inside the coal pile to prevent the coal pile spontaneous bustion. The wide adaptability of this method, but the cost is high, but also increases the ash content of coal, coal influential. (5) So that the coals to maintain proper hydration can prolong the oxidation of coal, to effectively prevent the spontaneous bustion of coal. According to the analysis, the spontaneous bustion of coal moisture is for 5% to 7%. When the moisture content of coal is of 12%, the coal will not ignite. The bottom of the coal storage field and should be used around the concrete structure to prevent water leakage and wastage. The coal yard set around spraying water facilities, sprayi