I have a Vacuum Motor from a material loader that might pick up coal. It was used to loader plastic pellets into a feeder on a plastic injection molding press. The wires were getting too short on it for the maintenance guys to use anymore.
I would check a local bearing supply house for auger flighting to fit into a five or six inch pipe, then build the drive train. A bigger diameter auger conveyor running slower will carry as much as a small fast running one will.
A chain conveyor will work but will be harder to build, First you need the frame work to support the conveyor chain, the detachable farm chain with attachment links can really add up in price,
An auger conveyor is fairly simple to build but requires support bearings at longer lengths. The support bearings are usually made from Lignum vitae, a tropical hardwood.http://en.wikipedia.org/wiki/Lignum_vitae
Lignum vitae is so dense it will sink in water, it is also self lubricating.
For longer length conveyors steel pipe is preferred, as it can span longer distances than can PVC with out support.
You can build two conveyors one to run the coal back to the bin horizontally and a second one to elevate the coal to the ceiling.
A transfer hopper would have to be installed also. Both augers need to be the same size to prevent the elevating auger from over flowing the transfer auger. Or the elevating auger can be smaller to prevent that also.
When I build my building for the stroker and the coal bin I am going to use an auger to bring the coal in from outside to deposit it in a hopper bin with an auger bottom to feed the hopper on the stroker.