BillK wrote: I can't believe there are no plans for a coal bin on the internet.
The only place they would be is here, hence the reason you can't find them. There's really no other forum or information except maybe at http://www.hearthnet.com
but they deal mostly with wood.
Basically you just build a box, the access door I mentioned and making sure there is access to the top is whats important. You need access to the top if you want to get it delivered.
Besides that building it sturdy enough, 3/4 is preferable. Those ratchet straps can come in handy, put eyebolts on the inside of the bin in the center on each side. then use the ratchet strap to keep it from bowing out. The reason for the ratchet straps is once you get the coal out you can take the straps out and they won't be in your way.