How far from pillar workings must trolley and feeder wires and transformers be located?

The correct distance that trolley and feeder wires, as well as transformers, must be located from pillar workings is 150 feet. This regulation is crucial for maintaining safety within underground mining operations. The distance helps to minimize the risk of electrical hazards and ensures that potentially disruptive electrical activities do not interfere with the stability of the pillars, which are essential for supporting the mine structure.

By adhering to this 150-foot requirement, mining operations can reduce the chances of electrical fires, short circuits, or other electrical-related incidents, particularly in environments where dust and moisture may exacerbate risks. This distance is established to facilitate safe access to necessary electrical equipment while protecting both miners and the structural integrity of the mining operations.

Other distances cited in the options either do not meet safety standards or may increase the risk of hazards associated with electrical systems in the mine. Therefore, 150 feet is the established and safest distance for the placement of these electrical components in relation to pillar workings.