Which statement best describes the 50m/24hr provision for stonedusting?

• A. Each 50m length of roadway that is being driven is stonedusted immediately after being driven.
• B. Each part of the roadway is stonedusted within 24hrs after being driven.
• C. Or if there is sufficient natural make of water associated with the mining operation to prevent a coal dust explosion.
• D. All of the above.

Answer: (D)

Stonedusting is used to control coal dust and prevent explosions, so the timing rules are about keeping that control up as roadway is advanced. For every 50 meters of roadway that has been driven, the stonedusting should be done either immediately or within 24 hours of driving. The provision also allows an exemption if there is enough natural moisture in the operation to prevent a coal dust explosion, meaning dusting isn’t required in that case. Because these aspects all describe how the 50m/24hr rule can be applied and when an exemption may apply, the best description is that all of the above are correct.