Sue,
I apologize and stand corrected. Usually these plants are located near their primary raw material source(limestone)to save on transportation costs. They must barge it in from elsewhere on the sound which is a low cost transportation method.
Typically this type of facility is not a good neighbor because of all the dust generated, which is another good reason for distance.
This goes back to the exceptions to every rule mantra.....

Again, apologies.

gimpy