Different ions precipitate out of solution at different concentrations. So calcium carbonate and calcium sulfate precipitate out first, then the sodium chloride, and potassium and magnesium will precipitate last. So you can pump the brine between different evaporate pans to concentrate the NaCl and get less of the other ions.
And Potash (KCL) is mined in large quantaties the same way salt is.
Or recovered from salt water the same way sea salt is. I used to deal with this company before it changed the ‘chemical’ in it’s name to "mineral’s and chemical Potash was reclassified as an organic fertilizer.
I feel like I’m going to get bounced for asking a very silly question, but here goes:
When I first pondered the sources of dietary salt a few years ago, I was sure that there was some that we got from animals we eat. After all, I could recall several references over the years to salt licks. (Yes, I knew about salt mines.)
So… if animals such as “deer, …cattle, …domestic sheep, …goats” and others get salt from salt licks, and those of us who are non-vegetarians eat their meat, why don’t we get some salt in out systems that way? 
We get salt from nearly everything we eat. What is the source of your confusion?
Well, I didn’t feel any confusion until I took an adult ed course in basic nutrition. The instructor seemed convinced that dietary salt was only something added to food, not naturally present, as I assumed it must be. Before posting I searched online in vain for a reference to naturally-present salt. After reading your reply I did some more searching and… found some references, not onlywith animal flesh as a source, but with plant as well.
So… :o
never mind
In Kraków: One cathedral, some chapels, several chandeliers, lots of sculptures - all hand carved by the miners and 200m underground. The Poles made a great deal of money from the mines in the Middle Ages and helped form several family dynasties, so they were strategically very important.
It and the city tour are quite a nice contrast to an Auschwitz Tour.
With all of the mining and machinery that goes into getting the salt, how is it that a pound of salt goes for twenty cents when it’s on sale?
Volume. They sell lots of salt.
You need to differentiate between stuff that the animals eat to keep their own bodies running, but which is “used up” during that process (for example, sweated out or used by chemical reactions that bind it, then excrete it) - and stuff that animals eat that’s stored in their system and thus passed on to the next level of food chain, like you. Unfortunatly, the latter happens mostly with unwanted stuff like heavy metals and hormones and pesticides, and not with the nutrients we need.
If you think about it: why do you need regularly to replenish your salt stores? Because your body looses it. The same happens to animals bodies.
The other problem from a nutritionists perspective is how much contents and amounts differ from one area to the next and one herd of cows to the next etc. So you might be okay = get enough salt eating cows from Wyoming (WAG) this year, but not steers from Texas next year. Therefore, the best recommendation is to add a bit of salt regularly, but not too much.*
In ages past, people were able to subsist for quite some time without additional salt in their diet in some areas, badly in other areas, until they, too, needed salt again. (Apart from, as already mentioned, the conservation issue, where you need a lot of salt to keep meat from spoiling).
- Similar problems for vitamins and other nutrients.