Safety precautions when lighting (1977)

Coal mine.

Various artificial light sources on the sections.

Searchlights.

Excavator operator in the excavator cab.

Panorama of the coal mine.

Suspension of the lighting line.

Spotlights on the supports.

Grounding.

Gas discharge lamps.

Excavator in the quarry.

Diagram of the electrical system.

Stress relief before starting repair work.

Conducting grounding.

Replacement of burnt-out lamps.

Coal mine at night.