brown coal 10 Associations

lignite wood coal coal (generic term) humate (generic term)

humic shale 11 Associations

shale (generic term) humate (generic term)

lignite 7 Associations

brown coal wood coal coal (generic term) humate (generic term)

peat 4 Associations

vegetable matter (generic term) humate (generic term)

wood coal 9 Associations

lignite brown coal coal (generic term) humate (generic term)