In the new update, you can combine 9 coal pieces into a block of coal. While this block of coal can be used for a nifty decoration, a single coal block can smelt 80 items while 9 pieces of coal will smelt only 72. Therefore coal (when compressed into a coal block) is more efficient. Also blocks of coal are more convenient to store than coal or charcoal by itself. Due note that you CAN'T use charcoal to make coal blocks.
Still I must conceded, in overall practicality charcoal is is preferred as it is easily obtained by wood blocks which easily grow from trees. For coal to be viable, I would have to recommend not only charcoal's use as a fuel nerfed but also wood products (stick, planks, wood block, wood stairs, ect) be nerfed as well. Basically, all charcoal and wood products smelting capability be halved. This way, one charcoal can smelt 4 items instead of 8, one wood block will smelt 0.75 items instead of 1.50, four planks will smelt 3 items instead of 6, eight wooden slabs smelt 3 items instead of 6, and eight sticks will smelt 2 items instead of 4. This nerf will make coal a more desirable resource but charcoal still be of some importance thanks to its availability and ease of creating. Without such a nerf, no one would bother to mine coal unless they happen to come some in an iron mine.
Lastly, I noticed that glowstone was NOT listed on the nation mine. Since glowstone is a is the main material used in glowstone blocks and glowstone lamps (both aesthetically pleasing light sources), as well as being an enhancer for potions in vanilla MC and being a useful prop item for RP, I suggest that a glowstone mine also be added. Seeing that the elves have only coal and emeralds (both of which are consider "mostly useless" by the community as of now), I suggest that the elves have a nation glowstone mine. It can be another unique material found only in elven lands and brings the number of minerals found in the Elvish lands up to 3 like the other "core" races. Of course there may be other plans with glowstone that I am currently unaware of but nevertheless I think it should be something that the administration should consider.