Just bought a coal/wood stove at a garage sale. Markings make it a Buckwalter Sure Luck Heater 316. Have been able to find no info elsewhere on the internet. Is it a cylinder stove? If so, why no door other than ash/vent door? Only other openings are the flue and the top burner. Any info you could provide, as well as what kind of coal to use and how to acquire it, would be GREATLY appreciated!!!