Agricultural salt/mineral blocks are not particularly well-utilized by wildlife.
What works much better is to simply load an old semi-rotten hollow tree stump with rock salt and let it leach away. Deer will virtually knock it apart and level it over time. I keep two or three active on the farm ... and no, don't hunt deer there, nor does anyone else. Although the the salt/mineral blocks are available to cattle in each field, I've never seen a deer at them, nor deer tracks nearby. They prefer the "salt stumps".