If an electrical interlock is chosen, the mine operator must obtain from MSHA a modification of the machine approval by way of the Field Modification Program by the mine operator or the conveyor manufacturer must seek a revision of the approval. Pictured is a sample Arm Rest Interlock Switch. When the operator leaves the chair, he must lift the armrest. This in turn de-energizes the conveyor. The conveyor remains de-energized until the operator resets the circuit by turning a reset button.
Proper training is important to minimize accidents.
However, a fail-safe system, especially one already available, gives obvious safety advantages. The mining industry is strongly encouraged to consider and adopt this suggestion. MSHA believes that unnecessary injuries and fatalities could be avoided in the future as a result.