CO concentrations in a mine entry are typically detected at which height?

CO concentrations in a mine entry are typically detected at which height?

• A. Floor
• B. Mid-height
• C. Ceiling
• D. Throughout the entry

Answer: (B)

The key idea is monitoring in the breathing zone. Carbon monoxide is a hazard that miners inhale, so detectors are placed where workers breathe—roughly chest to shoulder height. In a mine entry this mid-height position, about 4 to 5 feet (roughly 1.2 to 1.5 meters) above the floor, best reflects the CO concentration miners are exposed to. If detectors were on the floor or the ceiling, readings could misrepresent actual exposure due to air movement and mixing. By locating CO sensors at mid-height, the readings accurately indicate what workers would experience in normal operation.

The key idea is monitoring in the breathing zone. Carbon monoxide is a hazard that miners inhale, so detectors are placed where workers breathe—roughly chest to shoulder height. In a mine entry this mid-height position, about 4 to 5 feet (roughly 1.2 to 1.5 meters) above the floor, best reflects the CO concentration miners are exposed to. If detectors were on the floor or the ceiling, readings could misrepresent actual exposure due to air movement and mixing. By locating CO sensors at mid-height, the readings accurately indicate what workers would experience in normal operation.