| With the mineral exploration activities, the problems of geological prospecting are increasing. The surface, shallow mineral basically or mostly have been found.over time, relying on field geological observation of underground minerals will be more difficult to find. Geological exploration will be in the direction of the division of labor cooperation development for the geological, geophysical and geochemical exploration. Among them, geophysical exploration is playing the role of main force structure in the search for hidden underground ore body.The geophysical prospecting methods such as magnetic method, electric method, Gravity method, seismic method and so on are mainly used to study the geophysical field signals received by the ground.The analysis of physical signals and looking for the underground geological structures or ore bodies caused by changes in the geophysical field or abnormal are needed to To achieve the purpose of finding underground concealed ore body.In numerous geophysical exploration methods, the magnetic method has the characteristics.of the reflecting clearly On the magnetic ore body and Maturing in processing technology. Through the analysis of the data of magnetic measurement, we can study the characteristics of occurrence, size and shape of concealed orebodies, and guide the geological prospecting. At the same time, for large geological structures, especially fault structures, the surface magnetic method can also be divided into obvious anomalies, which is of guiding significance for the study of regional geology.The magnetic anomaly inversion is mainly to various mathematical processing of collected data. through the various means, strengthen the useful signal in acquisition data, get rid of the interference signal, and, produce for intuitive understanding and geological information corresponding to the magnetic anomaly through a variety of transformation. Geomagnetic field signal is a composite of various magnetic field superimposed signal, which accounts for the main body of the earth's magnetic fields produced by its own T0, and we have to look for underground ore body and the magnetic field generated by the magnetic field is superimposed on the magnetic field weak magnetic field. Therefore, in order to analyze the magnetic anomaly produced by the underground ore body, we first need to subtract the geomagnetic field T0 from the total field T of the geomagnetic field, leave the relative magnetic field ?T caused by the geological difference. In the actual work, T0 value depends mainly on finding a stable area in the magnetic field of in the survey area and measuring by the magnetic field to get the base value T0. While in the region with large interference, there is a large deviation between the T0 value and the real value, which results in the magnetic measurement data being too large or too small. This has a significant effect on the qualitative analysis of anomalies, especially in distinguishing shallow ore bodies and deep ore bodies.At present, the field measurement of magnetic field is the main field measured the total field value T. In this paper, the basic part T0 of the total magnetic field value T is obtained by processing mathematically the collected T values and the statistical approach, which is taken as the T0 value selected by the later data processing charting. Through the calculation of the model and the example calculation, we found that this method has a good effect on obtaining the T0 value in the magnetic anomaly signal under shallow ground ore body or high background field, but in practical application, it needs to combine the geological condition, adjust the coefficient and select the best value of T0, so that magnetic anomalies can be better consistent with the geological situation. |
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