So, after a long break from DF I've started a new fortress, and had an idea for my dining hall - A fireplace, I'm not sure of the feasibility of this, though, my plan at the moment is to have a magma pump-stack bring the magma to the dining hall level, then use a flood-gate system to drip a little magma (ideally just 1-2depth, to avoid flooding the fireplace in magma) into the fireplace and light whatever is inside it on fire, to add fuel, I'll put a pit/dump zone a few Z-levels above the fireplace to drop fuel in from a safe distance, to keep the fire from burning the dining hall and nearby dwarves, I'll have the fuel 1/magma mix 1 Z-level below the hall, then on the level of the hall some glass or gem windows (also keeping the smoke from spreading into the dining hall to avoid unhappiness and collapsed lungs, etc.) and will bring the smoke up to the surface (or to a cavern, depending on what level I put the fireplace)
my biggest concerns, at the moment, are:
What is a good fuel source? I don't know how long materials burn, so, about how long can I expect a fire to last in a contained manner this way, and ~how much should I expect to dump into the fire to keep it burning indefinitely?
Will I need a full-time team to keep it burning?