The main electrical distribution network for an underground mine is typically 4. 6 kV, 11 kV, 12,5 kV, 13. 8 kV or even 25 kV for deep and very extensive mines. The choice of voltage is highly dependent on the load level, which is related to the depth and the size. Reference to specific products, equipment, or manufacturers does not imply endorsement by the Bureau of Mines. The application of electricity to the mining industry is a distinctive area of both mining engineering and electrical engineering.