I would imagine they would tell you that it is not legal since the soil contains an attractant that was put there by man and not a natural accurance, and the minetrals in the soil are not there for the benifit of the cattle , and the fact that you know that the cattle are no longer present and you know the mineral deposits are there in the soil not for the cattles benifit but now solely for the benifit of wild animals and deer....that the site is considered baited... unless you remove all soil conataining the attractant and then wait ten days after removal before you hunt the site......... But I may be wrong!!!!!!!!!!!!!..................You need to contact the IDNR for clarification!!!!! You really dont want to be stradeling the fence on hunting legality issues with the IDNR................ hunt fair, hunt legal and you'll have no worries... none of it is worth risking your Hunting Rights.
In the case of .....if the cattle were still present it would be legal to have out salt or mineral lick attractants with the intention of for use by the cattle or other livestock... the deer frequenting the lick would be secondary and not the intended use of the licks.