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In this article we present an attempt to relate the intensity of the mechanical work done in ball milling processes with some characteristics of the sound recorded during these milling runs. In order to reach this purpose the ball milling sound was recorded at several vial frequencies in a broad range from 14 to 40 Hz, with and without a powder charge. This charge was of two distinct types: Al+Fe2O3 or Fe2O3. Two kinds of parameters were proposed to describe quantitatively a milling sound record: total root-mean-square power (dB) and 75 (95) percentile. In order to prove the validity of these results a comparison was made with the rate of energy transfer necessary to reach the displacement reaction between Al and Fe2O3. The reaction ignition was apparently delayed, for milling frequencies in a narrow range around 35 Hz, which can be explained in terms of a decrease in the rate of energy transfer as suggested by the sound parameters aforementioned. There is general consensus, between ball milling researche...