The monitoring of tailings dams, crucial to prevent accidents, is based on visual inspections and geotechnical instrumentation. Due to recent incidents, enhancement has become crucial, leading to the inclusion of geophysics in this study. Therefore, aiming to improve conventional monitoring during and after the alteration of two dams located in Catalão, Goiás, a campaign was conducted to obtain six electrical resistivity profiles to assess subsurface saturation conditions. Additionally, a microseismic monitoring system was implemented, involving fifteen seismic stations. By analyzing anomalies identified during the campaign in May 2022 and geological sections, it was possible to identify areas with unexpectedly high moisture content in places where such occurrences were not expected. Conventional microseismic monitoring revealed that most detonations did not significantly cause the mass to vibrate worryingly, with alerts primarily triggered by human activity and machinery movement. However, in the case of passive microseismic monitoring, due to the short monitoring period, no significant variations in the velocity percentage were recorded to enable a conclusive analysis of the mass s behavior.