I'll have to get some pictures this summer of a couple salt licks that haven't been salted in probably 15-20 years. Idaho used to allow hunting over salt, but they don't anymore. Some cabins that we go to in the summer have a salt lick that can hold 30 elk without seeing them from ground level. Another about a mile away is big enough that you wouldn't see me standing on the roof of my house if it was in there, and my house is 3000 sqft and 2 stories tall. Every single morning and evening you can expect to see an elk herd coming in. The amazing thing is that when a tree falls into the lick it must absorb the salt, because the elk eat it like nothing you've ever seen. An 18" diameter fir will last only 2 or 3 years laying in the bottom of one of those licks.