Regular monitoring of coal temperature at stockpile shall be carried out at points not more than _____________ apart, giving special attention to the corners of the stockpile.

• A. 2 meters
• B. 4 meters
• C. 6 meters
• D. 8 meters

Answer: (B)

Regular monitoring of coal temperature in a stockpile focuses on detecting hot spots early to prevent spontaneous combustion. To catch any rising temperature quickly, measurements should be spaced so no part of the pile is left unchecked between readings. Four meters apart achieves a practical balance: it provides frequent coverage to reveal hot spots promptly while keeping the work manageable for the crew. Corners of the stockpile are particularly important to monitor because airflow is often reduced there and moisture can accumulate, making these areas more susceptible to heat buildup. If measurements were spaced farther apart, such as six or eight meters, a hot spot could develop and grow undetected between readings. Conversely, measuring every two meters would be very thorough but unnecessarily labor-intensive for typical operations.