The dynamic process models reported so far in literature have ignored the fact that there are critical points of change over to chaotic dynamics during the progress of blow in a BOF. These critical points usually change the path of the blow profile and lead to either dry slag formation or slopping. The end point values of phosphorus, carbon and temperature may be severely affected by the occurrence or critical points. Hence it is of great practical importance to track these points online. A discrete dynamic analysis of the blow, while being tracked by a discrete surrogate model, helps to reveal the possibility of occurrence of the critical point in advance so that a proactive action can be taken in time to avoid the critical point altogether or better manage the situation with time. The “slopping” indicators based on sound measurement do help but are too late to act upon. Chaos control is necessary during the blow for control of phosphorus, carbon, and temperature at tap.