Biochar is useful in that it actually has low fixed carbon and high volatile content (plus ash). Charcoal is wood that has had the volatiles boiled off (charred) at high temp, leaving behind the inert (fixed) carbon as a sponge-like skeleton structure that absorbs water for water retention and releases some of its ash as mineral nutrients.
Coals range from anthracite ; bituminous ; semi-bituminous ; sub-bituminous (A, B & C) ; lignite (A & B); peat
Anthracite has high fixed carbon and little or no volatiles, through to peat which has low fixed carbon and high volatiles content.
dried peat is a good soil improver. no processing required
lignite can be charred, B will become powdery while A will retain as lumps. Victoria ( La Trobe valley) has billions of tonnes of lignite B.
Anthracite has little or no volatiles so is of no use for this purpose.
