South African contractor Concor,in partnership with OptiPower, has been awarded a R212-million contract for the structural foundations and associated infrastructure for 24 additional dishes for South Africa’s MeerKAT radio telescope array. MeerKAT currently has 64 dishes. The partners have also been contracted to design another 109 dish foundations and associated infrastructure. The project is currently in the design stage, with construction due to start in June.

MeerKAT is situated in a remote part of the Karoo region, in the Northern Cape province. A fully functional instrument in its own right, it is also a precursor to the international Square Kilometre Array (SKA) radio telescope and will, in due course, be integrated into it. (The SKA will be co-hosted by South Africa and Australia and these contracts may, in reality, be the first construction contracts for the South Africa-based SKA itself.)

Concor will be responsible for the structural concrete foundations for the 24 new dishes, as well as the construction of 40 km of gravel access roads and four gatehouses. The company will also have to erect a construction camp capable of accommodating about 250 people, complete with security fencing, water storage, sewage and wastewater treatment facilities and settling ponds.

OptiPower will electrify the works and provide fibre connectivity to the new dish sites. This will involve some 60 km of trenching, along with the required electrical power cables, fibre cables and fibre ducting.

“A key constraint of this current project is the need to limit any radio frequency interference (RFI) in the vicinity of the MeerKAT telescope array,” highlighted Concor contracts director Joe Nell. “This is due to the highly sensitive nature of the radio telescope equipment, which is designed to detect extremely weak radio signals from astrophysical sources.”

RFI signals are given off by cellphones, vehicle equipment and domestic appliances like microwave ovens. These can cause interference with the reception of weak radio waves from far distant galaxies and other astronomical and astrophysical phenomena. In extreme cases, they could also damage the array’s dish antennas.

As a consequence, the construction camp will be located some 15 km away from the MeerKAT instrument. Concor’s main construction office will be set up at Carnarvon, the nearest town to the MeerKAT, some 100 km from the radio telescope. As the time approaches to start the work, an insulated RFI container will be set up at the site, which will enable the contractors to communicate and to operate some electronic equipment, without interfering with the telescope.

Every vehicle and piece of equipment used by the partner companies will have to be checked for RFI emissions and certified, before being allowed on site. “We have employed an RFI expert to test our equipment and submit the necessary data to the client,” reported Concor site agent Roy van Leeve. “After careful analysis of this data, we will be granted a permit for that particular item of machinery or advised what steps need to be taken before machinery can be passed for use on site.”

Even the more conventional aspects of the project are demanding. “It is vital that the roads be well designed and constructed, especially in terms of their vertical and horizontal alignment,” he explained. “This will ensure that the low-beds and other heavy trucks delivering construction materials and large componentry can navigate the route safely.”

Further, the limited number of foundations to be constructed means that Concor’s usual practice of setting up its own on-site concrete batch production plant is not practical. The company will have to source the concrete commercially, which complicates the logistical aspects of the project.

Nevertheless, Concor believes that its experience in constructing eight wind farms (with another two in the process of completion) provides it with significant experience that can be applied to the MeerKAT project. “Contractually, we have been very successful in carrying out these projects efficiently and on time, in a spirit of collaboration that has overcome various challenges and earned us considerable repeat business from clients,” noted Nell.

The contractor will make use of small, medium-sized and microenterprises located in the local municipal area (Kareeberg). This includes the towns of Brandvlei, Loxton, Vanwyksvlei and Williston, as well as Carnarvon.