The closest we have to a limestone mine as such is the quarry complex at Beachville ON. A few minutes NE of Ingersoll ON, these quarries have been in some form of operation since the late 18th/early 19th Centuries--we even found a couple of lime kilns--beehive(ca.1890's?). The closest to a mine at present is the 'underpass' made to cross under the doubletrack mainline of CN(Dundas Sub). Apparently there was a couple of shafts back in the 70's but , alas, none are to be found as it is currently stripped.
The scale of any limestone mine is impressive, especially these ones.