Which statement best represents a situation where you do not require one entry to conduct return air from a part of the mine?

• A. A shaft being sunk, or a drift or roadway being driven where it would be impracticable to provide a separate return roadway.
• B. A shaft that has already reached depth and is fully ventilated.
• C. A finished roadway with a dedicated return airway.
• D. An area with no gas risk.

Answer: (A)

In coal mine ventilation, the usual setup uses separate intake and return airways to keep fresh air from mixing with exhaust. But there are times during development when it isn’t practical to drill or drive a dedicated return roadway yet. This is the situation described: a shaft being sunk, or a drift or roadway being driven, where providing a separate return roadway would be impracticable. In those cases, you don’t have to have a separate return entry right away because construction constraints prevent it, and you manage ventilation with the methods available until a dedicated return can be established.

The other scenarios describe conditions where either a proper return pathway is already in place or the lack of gas risk doesn’t remove the need for an appropriate ventilation return path. A finished roadway with a dedicated return airway clearly has a separate return, which isn’t the situation described. A shaft that’s already deep and fully ventilated implies an established system, not an impractical construction issue. An area with no gas risk doesn’t eliminate the requirement for safe, controlled ventilation pathways.