JB Switchgear Solutions was recently awarded a contract to design, manufacture, and supply of four containerised substations for the Gbeni site of Sierra Rutile’s mining operations. This was a unique project since the containers each had to house a MV/LV dry type transformer, and electrical switchgear. This containerised equipment had been put onto a skid, and these skids were built to be movable around the mining site.

The substations/skids were broken up into four: Two booster skids/substations, one mining in-pit skid/substation and a scrubber skid/substation. The containers for the booster skid and mining in-pit were made into 7 m lengths and were split at the mid-point by a partition wall, so that one side housed the dry-type transformer, and the other side housed the LV panels.

The booster substations were also 7 m long, and each housed an 800 kVA dry type transformer on the one side of the container and the LV panels on the other side. The LV section housed the MCC, which consisted of an incomer rated at 1250 A, which fed two 260 kW free standing variable speed drives (VSDs) in the container. These VSDs were used for the slurry pumps on the skid. The LV section of the container housed a 250 A PFC panel as well, which was fed from the MCC.

The mobile mining unit/mining in-pit substation was also 7 m long and housed a 1600 kVA dry type transformer on the one side of the container. The LV section housed the MCC, which consisted of an incomer rated at 2000 A, which fed two 160 kW soft starters, as well as a 355 kW free standing VSD, which is used for the gravel pump. The LV section of the container housed a 400A PFC panel, also fed from the MCC.

The scrubber substation was initially a 12 m container, but due to skid restraints, was cut into half. That is, it was now two containers, with one feeding the MCC panels in the other container via an encapsulated busbar system. The set up was the same as the previous containers. One of the 6 m containers was divided to accommodate the 2000 kVA dry type transformer which fed the LV panel with an encapsulated bus-bar system. The LV section housed the MCC which featured a 2500A incomer. The panel consisted of 15 DOL starters, plus a few feeders.

The second incomer had a second incomer rated at 2500A as well, which was fed from the first container. This container housed a 200 kW wall mounted VSD for the water booster pump, two 260 kW VSDs for the trommel underflow pump, and two 330 kW VSDs for the scrubber trommel. The LV section of the container housed a 400A PFC panel, also fed from the MCC.

Contact JB Switchgear, Tel 011 027-5804, info@jbswitchgear.co.za