Collier; Coal Miner
This page is the CodyCross answer for the clue below from Farm, Group 480, Puzzle 4 (Controlled Atmosphere).
Question is: Collier; Coal Miner
and the answer is: PITMAN
Word Meaning:
PITMAN — (plural "pitmen") One who works in a pit, as in mining, in sawing timber, etc.
Definitions from Wiktionary.