South African Gold Mines: Maximum Suspension Depth for Type 9 11kV 3×120mm² DWA Shaft CablesComplete Engineering Calculation Guide
South Africa’s Witwatersrand Basin contains the deepest operating mines on Earth. Mponeng operates at 3,800 m below surface. South Deep reaches 3,000 m. Driefontein extends to 3,400 m. At these depths, a medium-voltage shaft cable must support its own weight — approximately 13–17 kg per meter for an 11kV 3×120mm² construction — over vertical distances that impose tensile loads exceeding 400 kN on the armour wires at the cable’s suspension point. Only SANS 1507 Type 9 double wire armoured (DWA) construction provides sufficient tensile capacity for these depths, and even then, engineering analysis must verify that the maximum free-hanging depth does not exceed the cable’s calculated suspension limit. This guide provides the complete engineering framework for that calculation.


















