[2021] To the devs: The problem with mining Coal

I was thinking about this thread the last time I was doing a buried supplies quest. I noticed there was a block of dirt that was basically black. Many individual textures span more than one block (to reduce the appearance of tiling), and there are different terrain textures for more horizontal or vertical surfaces, at least in some biomes. It looked to me like an unlucky combination of shape & rotation resulted in the black block.

You could try the burnt forest biome as an alternative source of coal.