Stone dust coverage for 200m outbye development and 400m outbye Longwall last row of completed c/t is which percentage?

Stone dust coverage for 200m outbye development and 400m outbye Longwall last row of completed c/t is which percentage?

• A. 75%
• B. 80%
• C. 85%
• D. 90%

Answer: (C)

Stone dust coverage is used to inert coal dust by coating surfaces with stone dust so that a large portion of the exposed coal dust is protected from ignition and flame propagation. The percentage describes how much of the relevant surface area must be coated in order to keep the dust explosive potential under control. In practice, different locations and distances from the face require different coverage levels. For the situation described, 85% coverage is required for both 200 m outbye development and 400 m outbye the last row of a completed c/t. This level strikes a balance between providing a robust safeguard against dust explosions along main returns and gob areas, and keeping the work practical. Lower coverage such as 75% or 80% leaves more uncoated coal dust surface and raises risk, while higher coverage like 90% would be more stringent than necessary for these zones.

Stone dust coverage is used to inert coal dust by coating surfaces with stone dust so that a large portion of the exposed coal dust is protected from ignition and flame propagation. The percentage describes how much of the relevant surface area must be coated in order to keep the dust explosive potential under control. In practice, different locations and distances from the face require different coverage levels.

For the situation described, 85% coverage is required for both 200 m outbye development and 400 m outbye the last row of a completed c/t. This level strikes a balance between providing a robust safeguard against dust explosions along main returns and gob areas, and keeping the work practical. Lower coverage such as 75% or 80% leaves more uncoated coal dust surface and raises risk, while higher coverage like 90% would be more stringent than necessary for these zones.