Different areas of the country often have somewhat different requirements in mineral programs. We feed a high mag mineral free choice in mineral feeders. Once the cattle get the amount they need they leave it alone. It is a loose mineral and they seem to do better with it than they do on a block.
We have also mixed it in with our creep feed or range cubes, but I think the cattle get what they need better on their own than forcing it in their diet with it mixed in.
In your case with the calf eating dirt, I might try mixing in a high mag mineral at one 50 lb bag of mineral per ton of feed and one 50 lb bag of loose salt per ton. That will get it in his diet. Not sure how much per day you are feeding him but guessing he is on show ration or close to it he will get those minerals quick. Best of luck to you whichever route you go.