Influências de estruturas metálicas na aquisição de dados eletromagnéticos obtidos com condutivímetro EM34

Metal structures (fences, wires, constructions) are sources of interference when using electromagnetic methods (EM) in environmental or mineral prospecting studies. With the objective of dimensioning the interference caused by metallic wires, a three-wire fence simulating, we conducted a study in two areas located in the University of São Paulo (USP), where each area with different values of conductivity used the EM34 equipment. The measurements were performed in the same positions (HCP and VCP configuration loops), initially without the fence, then placing the fence. Two scenarios were simulated, first with the wires not connected to each other (not forming turns) and another with the wires connected, simulating reinforcement structures normally used in farms with animal husbandry. The results show that EM34 is sensitive to the presence of the fence for HCP loop in both areas studied. For the VCP loop, the distortions caused by the fence were larger in the area with higher conductivity. A simple field test is proposed to verify whether a fence can cause (or not) interference with the apparent conductivity measurements with EM34