is this Bituminous coal

Here's some pictures of it
First one was a big lump
other pictures are after i split it with a hammer, showing the previously unexposed side of the lump.

Also I'm wondering whether it's related to the brown gunk which is coming down the chimney - more of that here :
What's this brown gunk?

I would say it's got to be either Bituminous or SubBituminous.. you really can't tell from looking, you have to do an analysis on the coal. which most mines or breakers in the states would do. I don't know about the mines where you are.

The only way to tell between Anthracite and Bit coal is to put a piece on a hot bed of coals.. if it's Anthracite, it will just sit there, maybe pop or flake a piece off when it heats up or water turns to steam in a small spot.. Bit will fume, smoke, catch fire, burn with a yellow flame, smoke will often be yellow-gray.

The brown gunk is probably moisture, the coal may have a lot of water in it, and it is mixing with the fly ash when the coal is burned, making a muck /mud in the flue pipes..

Can you store a quantity near the stove, and see if it dries out [weigh it before/after] or just burn it after it has had a week or two to dry?

Greg L

It is good that you have nice big lumps available; the bigger the better.

That is probably bituminous coal. There is nothing wrong with that most of the coal-heating world and many people on this site heat with that type of coal. As I mentioned in the other thread, it is doubtful but possible that the black gunk coming out of your stack is related to the coal combustion and stack condensation. You need to make a better (larger) rain cap to keep rains even blowing rain from entering the flue if you are having this severe of a problem. Change the orientation of the flue pipe; it should be male end down and this concern would be eliminated regardless of the cause.

It is NOT coal tar, creosote or anything like that, it is likely simply moisture entering the stack and mixing with soot, but may be from high moisture coal and very low exhaust temps along with a large exposed outdoor pipe (single wall outside?) and very cold outdoor temps. Change the orientation of the pipe to the proper direction (male end down) and this won't be an issue.