NY has an essentially unlimited supply of rock salt. Most of the central tier of NY has salt beds 300+ feet think under it. All they have to do is dig a hole down to it and dig it out.
Yup. Where I went to school in Livingston county, you could look out the windows and see the piles and piles and piles of salt at the Retsof Salt mine. My old man used to drive the trucks on and off.
IIRC that deposit is thought to be the second biggest salt deposit in the world, there is one somewhere on South America bigger.