News & Media

April 2008

CONCOR PART OF JV TO BUILD BRAMHOEK AND BEDFORD DAMS

Concor Roads and Earthworks, lead contractor on the Bramhoek Dams Joint Venture, reports that the JV has been awarded the contract to construct the Bramhoek Dam and the Bedford Dam for the Ingula Pumped Storage Scheme.

The JV, comprising Concor Road and Earthworks, WBHO, Edwin Construction and Silver Rock, moved onto site in April 2008. The scheduled completion date for Bramhoek Dam will be March 2010 with its impoundment date being August 2009, while Bedford Dam is scheduled for completion in September 2010.

Eric Wisse, contracts director at Concor Roads and Earthworks, says that the Ingula Pumped Storage Scheme consists of an upper dam, Bedford, and a lower dam, Bramhoek. “Both will have an approximate water capacity of 22 million cubic metres. The dams are 4.6 km apart and are connected by underground waterways through an underground powerhouse which will house four 333 MW pump turbines.”

The site of the pumped storage scheme spans the Little Drakensberg, straddling the provincial boundary of the Free State near Harrismith and KwaZulu-Natal, near Ladysmith. “As the crow flies the distance between the upper and lower reservoirs is about 6 km with an elevation difference of 470 metres,” Wisse says.

The Scheme is located 23 km north east of Van Reenen within the Little Drakensberg mountain range. It involves an upper reservoir in the Free State Province, an underground power tunnel complex, and power station with a lower reservoir in KZN.

Bedford Dam is a 49 metre high, concrete faced rock filled dam with a total reservoir volume of 22.4 million cubic metres. It will have a 42 metre high intake tower with a 1 metre diameter reinforced concrete outlet conduit and a 15 x 45 metre energy dissipating basin. The rockfill embankment is 480 metres long.
 
Bramhoek Dam is an RCC (roller compacted concrete) dam. The wall is 330 metres long and 39 metres high. “It has an ogee-crest spillway with a crest length of 40 metres and the inlet and outlet works are located within the dam wall,” Wisse explains. Approximately 90 000 m3 of RCC will be used to construct the wall.

“One of the challenges on site will be the removal of some 80 000 m3 of peat prior to the actual foundation excavation being done for Bedford Dam,” Wisse says.

“Additionally, a challenge on Bramhoek will be to implement the river diversions timeously. The first stage river diversion needs to be completed before the rainy season begins in 2008.”

Over the past 32 years Concor Roads and Earthworks has built a reputation as a highly professional and competent road building and earthworks contractor in southern Africa. The focus of the division is the construction of major road projects, but its core competencies extend to all earthworks and mining infrastructure related projects.