Study On The Application Of Using TEM Detecting Water Hazards In Coal Mine

As one kind of time-domain electromagnetic prospecting method, the transient electromagnetic method (shorted as TEM) has been applied widely with it's advantage such as facility, express & sensitive on low-resistance in prospecting resource ,surveying and investigating hydrology, engineering and environment. It is the best choice of detecting water hazards in coal mine areas and has been become powerful resolution to ensure safety in coal mine producing.The paper aims at main aspects of central-loop TEM, such as the theory of detecting water hazards, modeling, data processing etc.Basically on Maxwell equation, induced solution of TEM response of horizontal layered medium using central loop unit widely applied in TEM prospecting. Introduced briefly on several most commonly method on inversion and interpretation. Summed up the main kinds of noises, analyzed the methods of canceling 50Hz AC as well as high amplitude noise according to their features in TEM data. Discussed the identification and suppression methods of the transient response that caused by the non-swirl, the methods of terrain correction, the methods of metal structures correction in mining area exploration. Because the forward & inversion theory of TEM is founded on vertical current pulse, the stimulation current turn off has ramp actually. So must be correct, and a simple correction is given. Introduced the basic theory of Solving two or three-dimensional TEM response by the finite element method (FEM). After considered the characteristics of electricity of earth and mining situations in coal mine, designed simplify model, and do forward calculations. The calculation results showed that resistivity sections and more measured performance curve maps obviously abnormal to reflect the actual situation of the water hazards in the mined-out area and mine water fault, but very low resistivity from shallow to deep link up, with prolonged phenomenon.Practical applications are also confirms the conclusions of this calculations, made a good geological effects and social benefits at the same time. The applications provided a strong guarantee for the efficient production of coal mine safety.