Recent investigations show that structure-borne sound sensors yield valuable information about the scrap melt period. Scrap shielding of the furnace walls against arc radiation can be computed by observing the EAF’s current waveform in combination with the structure-borne sound. Furthermore cold heavy pieces of scrap at the bottom of an arc can be detected. The obtained information can be used to control and optimize the power set-point of the EAF. Improved performance in power-on time, productivity and furnace wear should be the consequent result.