Sources of seismic noise in an open-pit mining environment

We present the characterization of the sources of vibration in the open-pit Riotinto mine (southern Spain), based on the data recorded by a dense seismic network of 30 stations located along a 1-km long segment of a tailings dam. We describe the most common transient signals detected, including local and distant earthquakes, blasting and vehicles. The time variations in the amplitude of the 10-40 Hz frequency band are then used to define three phases of activity during the recording period. The phase with the highest seismic amplitudes is observed during a time interval of five weeks, coinciding with the civil works carried out for the regrowth of the dam, necessary to correctly capture the continuously increasing amount of tailings. In the last three months of operation of our network, the seismic noise is dominated by the deposition of tailings into the pond, enabling the use of seismic data to monitor into detail the evolution of the deposition process.