With so many Tractor Supply stores opening here in Connecticut, an independent store carrying coal wouldn't make any sense.
By itself? No it wouldn't even around here. I have a buddy that sells coal on a pallet..... but he's on main road that a l lot coal customers pass by. He also sells bulk coal, , wood pellets, delivers wood coal/pelltes, refills propane, does custom fireplace/mantle work, sells coal and wood stoves etc.
If you were offering delivery you might get somewhere but remember if the customer calls you in the middle winter for delivery and you don't have any coal they are going to call someone else and keep calling them.