automatic locking - barren zone
- autotripper
- autotrophic
- autotype
- autozooid
- Autun shale oil
- Autunian
- autunite
- Auversian
- Auversian stage
- auxiliary
- auxiliary accessories
- auxiliary adit
- auxiliary blower
- auxiliary engine
- auxiliary fan
- auxiliary fault
- auxiliary haulage
- auxiliary lobe
- auxiliary measures to protect the roadway
- auxiliary mine-rescue team
- auxiliary mineral
- auxiliary shaft
- auxiliary team
- auxiliary ventilation
- auxiliary winch
- auxospore
- auxotrophic
- AVA
- availability of gas
- availability of oil
- available
- available data
- available ground water
- available head
- available moisture
- available precipitation
- available pressure head
- available surface of evaporation
- avalanche
- avalanche baffleworks