Electricity + Control February 2019

The 60 MVA, 88 kV/6.6 kV bulk electrical substation ensures secure energy supply to the mine and operations and is dedi- cated to the Cullinan Diamond Mine.

TRANSFORMERS + SUBSTATIONS

and a 6,6 kV overhead line from the bulk substation to the new 7 Dam pump-sta- tion. It also installed containerised MCCs, cabling and cable racking at the pump-sta- tion itself, as well as transformers and switchgear, MV and LV electrical reticu- lation, cable racking and cabling, lighting and a communication system for the mill expansion. In addition to this surface work, Enl Electrical was engaged underground on the mine’s C-Cut project – including MV and LV electrical reticulation, racking and cabling, lighting and communication sys- tem. The use of modern electrical and control technologies by the Zest WEG Group – such as VSDs and energy-effi- cient motors – will reduce power con-

sumption in the plant, despite the high- er processing capacity of 6 Mt/a of the new configuration. The redesign by Cullinan Mine of its process plant means that it covers a smaller area of four hectares, and is lighter on equipment. There are now 28 conveyor belts instead of 151, with a total belt length of 4 km, down from 15 km in the old plant. Transfer points have been cut from 179 to 48, crushers from 11 to four, screens from 88 to 25, pumps from 121 to sixteen, feeders from 21 to 14, substations from 17 to three, and electrical motors from 589 to 84.

The complete electrical construction scope as well as the installation of electrical equip- ment was executed by Zest WEG Group’s construction business, EnI Electrical.