IPA: /ˈkɒl.ɪ.əri/
KK: /ˈkɑːlɪəri/
A place where coal is extracted from the ground, including the mine itself and the buildings associated with it.
The workers at the colliery were busy extracting coal for the winter.
Coliery → It is formed from "collier" (from Old French *colier*, meaning coal miner) and the suffix "-y" (meaning a place associated with). A colliery is a place associated with coal mining or a coal mine.
Think of a 'collier' as a coal miner, and the '-y' indicates a place, so a colliery is a place where coal mining happens.