Abstract: In the operation of a top-blowing steelmaking converter having at least one blowing lance, the distance of said lance from the surface of the molten metal bath is controlled in dependence on the sound levels of the blowing noise measured through the slag at selected frequencies. In order to minimize the risk of slopping, the actual values of the sound levels measured at predetermined frequencies are combined to form a resultant value, the difference between said resultant value and a predetermined reference value, which is associated with a sound level and indicates that slopping is likely to occur, is determined, and said difference is used as an indication of the probability of an occurrence of slopping and is compared with at least one predetermined probability limit, the distance of the blowing lance and optionally also the oxygen supply rate is corrected when said difference exceeds said probability limit.