Under what condition can a person ride on a conveyor at an underground coal mine?

In the context of underground coal mining operations, safety is of paramount importance, especially concerning the use of equipment such as conveyors. The correct answer highlights that riding on a conveyor is permissible only if it has been specifically designed for that purpose. Equipment such as conveyors are engineered with particular functionalities, and if riding is not part of the design, it poses significant safety risks.

Conveyors generally transport materials like coal, and their primary function does not include carrying personnel. If a conveyor is designed for riding, it would typically incorporate safety features and guidelines to protect individuals from the hazards associated with the movement of materials, such as entanglement or falls.

While supervision, emergency procedures, and backup safety mechanisms all contribute to the overall safety framework of mining operations, they do not replace the necessity for the equipment to be designed for that specific use. Therefore, the fundamental condition for riding on a conveyor in an underground coal mine is that it must be constructed and approved for such use.