It seems that the purpose of the algorithm is to find the smallest value in a list of 30 values. These values all appear to be expected to be less than or equal to 100, hence the presetting of MIN to (default) 100. The first value in the list will therefore be less than or equal to 100 and the logic will set MIN to this value until a lower value is found in the list.
The algorithm as presented doesn’t show the scope of the FOR loop. Nevertheless, there seems to be sufficient evidence to show that the purpose of setting MIN to 100 is to provide an initial value which none of the values in the list can exceed.