to 61 cm below top 29 of steel melt 28 top 29 of the steel melt 28 is below slag layer 27 top 29 is referred to as interface 29 between slag layer 27 and steel melt 28 slag layer 27 may contain lime silica or other material slag layer 27 may be added to molten metal 28 in metallurgical vessel 30 prior to dispensing of additive wire 20 into molten metal 28 wire feeding apparatus 10 can have a means for displacing lance 12 along the front of structural member 40 such as motor driven chain 42 operatively coupled to motor 43 as shown in fig1 or a hydraulically driven unit such as a telescoping unit fig2 which can be driven in the extending and contracting positions motor control 35 is configured to control the operation of motor 43 which displaces lance 12 along a predetermined path motor 34 is also referred to as a position actuator and can be an electric motor for example encoder 44 which can be an analog device for example is configured to track the movement of lance 12 in both movement directions 47 relative to laser device 22 and or relative to vessel.