Due to some incomplete research about a year ago I came to the exactly incorrect conclusion that I needed to use anthracite coal in my newly built forge. I bought a pickup truck load of it. My first attempt at blacksmithing didn’t last long (that’s another story) but now that I’ve built another, better forge I still have most of that truckload of coal. It gets hot enough to forge mild steel, for sure I know that so far: Can’t weld with it, also so far, and I haven’t tried it on tool steels or stainless yet. (I’ll let you know next week how that goes). Long story short though: I paid for it and I’m going to use it for something at least. My experiences with it match everything described here.