Where must continuous monitoring sensors be installed to detect products of combustion?

• A. Return side of each conveyor belt
• B. In the intake air near the portal
• C. In the ventilation shaft
• D. In the miners' break room

Answer: (A)

This tests where to position continuous monitoring sensors to spot products of combustion quickly. In underground mining, smoke from a conveyor belt fire travels with the ventilation flow toward the return airway. Placing detectors on the return side of each conveyor belt puts them directly in the path of that smoke, giving early warning and enabling rapid response before the fire affects fresh air or spreads further. Detectors on the intake air near the portal would miss or delay detection of belt-fire smoke, and detectors in the ventilation shaft or in a break room aren’t placed where belt-fire smoke first travels. So the return side of each conveyor belt is the most effective location for prompt detection.