in MMO

https://lifeisfeudal.gamepedia.com/Category:Ground_raw_materials#Terrains

In MMO, new substances have been added. Is it possible to add them during generation with the possibility of choosing what to mine, process and receive new materials for recipes?

Hi,
not unless devs patch those new substances into YO i'm afraid

1. I can write a new cm_substances.cs
you will need to add a singleton Substance (NewMaterial) for the material and a singleton Substance (NewMaterialFragments) for the poured materials (you can add coal as well;)).
2. add materials to objects_types.xml, which will not be so difficult
3. Then it will be necessary to add it with a patch after loading the map, only they can be mined not as ores (there are abilities), but as substances (digging tunnels): stone, granite, clay, etc.