Answer:

culm

Answer	Crossword Clue
CULM	River in Somerset and Devon
CULM	Coal dust.
CULM	Hard coal refuse.

CULM	Hollow, jointed stem of a grass.
CULM	Jointed stem of a grass.
CULM	Coal refuse.
CULM	Coal dust
CULM	Slack
CULM	Refuse coal screenings
CULM	Grass stem