Bituminous coal is found in veins in sedimentary layers and is one of the two mineral sources of fuel. When processed at a smelter or magma smelter, one unit of bituminous coal produces 3 units of coke. If done at a regular smelter, this processing requires one pre-existing unit of fuel (either charcoal or coke), leaving a net production of 2 fuel.
Bituminous coal is flammable, and obviously is not a fire-safe material - if exposed to fire or magma, an item made of bituminous coal will burn for the better part of a year before wearing away. Exposure to water (including rain) will extinguish it, unless it happens to be stored in a bin.
Bituminous coal is not the same as "refined coal" or "coal", though it is directly related.
[INORGANIC:COAL_BITUMINOUS] [USE_MATERIAL_TEMPLATE:STONE_TEMPLATE] [STATE_NAME_ADJ:ALL_SOLID:bituminous coal][DISPLAY_COLOR:0:7:1][TILE:15] [ENVIRONMENT:SEDIMENTARY:VEIN:100] [ITEM_SYMBOL:15] [SPEC_HEAT:409] [IGNITE_POINT:11440] [MELTING_POINT:NONE] [BOILING_POINT:16708] [SOLID_DENSITY:1346] [IS_STONE]