【導(dǎo)讀】desertification.50%)andwater(generallybetween2%to20%change),thesesubstancesis. bustion.

　　

【正文】 a large number of cracks, which is bound to accelerate the upward migration of radon gas speed, can be formed on the surface a high radon anomalies. In addition, the spontaneous bustion of coal and surrounding rock, there is a large number of pores, and contains a certain amount of moisture and different degrees. The local existence of heat source, the superheated steam can change the moisture content of the pores in the rock, according to made the emanation coefficient experiments showed that the emanation coefficient in the presence of pore water can increase the pore. Therefore, the role of the underground hot steam can increase the concentration of radon in the pores of the rock. By the above discussion, the paper argues that underground somewhere in the coal seam spontaneous bustion in the coal seam and its surrounding conditions 16 substantially are the same, will increase the migration rate of the spontaneous bustion zone at the top of radon. Therefore, the apparent differences in the concentration of radon in the top of the hot zone and without the top of the hot zone will be. If you use the appropriate method to detect and extract this difference, we can determine the location and scope of the underground spontaneous bustion of coal seam at the surface. Geological radar coalfield Spontaneous Combustion Geological radar (GPR) is the use of the UHF shortpulse (1 ~ 1000MHz) electromagic waves to detect subsurface distribution of a highprecision geophysical methods. Will be reflected when the transmitting antenna launching the highfrequency electromagic waves in the form of short broadband pulses into the ground, electromagic wave propagation in the subsurface, Dielectric different varying degrees of attenuation, encounter different dielectric properties of the interface the reflected signal receiving antenna to receive the digital signal processing to the electrical distribution reflects the subsurface radar images. Can be analyzed and verified with specific geological conditions, which proved the distribution of Coal Spontaneous Combustion, and provide the basis for firefighting operations. General raw coal has a high conductivity, spontaneous bustion on the overburden longterm coal seam spontaneous bustion baking, moisture content, low conductivity, the huge power difference can distinguish the original coal seam and surrounding rock。 bee the partial oxidation of coal seam after spontaneous bustion or plete oxidation of coal, its 17 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. 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. 18 (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 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 19 the concrete structure to prevent water leakage and wastage. The coal yard set around spraying water facilities, spraying water to the coal pile on a regular basis, doing so ca