ventilation level

adit for air ventilation in a mine. 
air level, ventilation road

OverviewRelatedTableS1S2S3

Wikidata
return air level, intake level, level, underground mine ventilation, 

• Google Knowledge entry^@
  

intake level – level – return air level – 

Type	Date	Description	Keywords	Notes	Source
link		Google Knowledge entry@			Wikidata

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