Construction World April 2019

settlements,” he says. They were placed on geogrids that were spread throughout the area that received G7 material. The geogrids were positioned at two metre heights of the fill material, with the geotextile membrane placed underneath and at the back of the Terramesh boxes for filtration purposes and to prevent the loss of fines. Macdrains were then installed along the full length of the embankment for drainage purposes. Spread across the 70 degree-angled slope of the embankment, they separate the fill and in-situ material to enable seepage water to drain down to the 110 mm-diameter perforated pipes. The water is then drained out of the wall via transverse pipes that were installed at 50 m intervals along the length of the face. Security fence and guard rails were also installed in front of the wall as further protection measures to complete this component of the KwaNobuhle Area 11 – Link Sewer project. Importantly, this labour-intensive construction method provided

many employment opportunities for members of surrounding communities. A total of 18 small, medium and micro enterprises (SMMEs) from various wards of the NMBM were also sub-contracted by the principal contractor to build the retaining wall. Arrangement of the many work packages and management of the SMMEs was an extremely complex undertaking. A fulltime SMME construction manager was, therefore, appointed to assist in the management and training of these emerging contractors. Certainly, working in built-up areas also provided its share of challenges during the construction of the pipeline with the principal contractor having to contend with many hidden services. Nyoka notes that, despite the challenges and technical complexity of the project, it was delivered according to standard, drawing and specification – a feat he attributes to outstanding participation of all members of the professional team right from the outset. 

EXPERTISE FOR BELFAST MINE Concor Infrastructure is building dams, roads, platforms and other works at Exxaro’s new digital coal mine near Belfast in Mpumalanga province.

A t work since October 2017, Concor Infrastructure is constructing four major dams, 26 concrete platforms and terraces, 37 internal roads of 16 km in length, and the upgrade of almost 13 km of provincial roads, among other aspects of the mine. According to Concor Infrastructure contracts manager Pierre van Vuuren, dams are being lined with both a geosynthetic clay liner (GCL) and high density polyethylene (HDP) sheets, in compliance with the water use licence and related environmental regulations. Various structures around the dams are also being installed, including large silt traps, drying beds, inflow chutes to prevent scouring, and spillways and sumps. Among the concrete platforms and terraces are two primary crusher bases being built for the run-of-mine crushing facilities. The various structures being built by Concor Infrastructure on the mine will demand almost 350 tonnes of steel reinforcing, and nearly 2 700 tonnes of bulk cement. Other inputs will be around 15 000 tonnes of 19 mm aggregate and nearly 13 000 tonnes of crusher sand. Extensive upgrading is being done on the D1770 and D1110 provincial roads – for the transport of coal to the rail siding –

including eight major culverts under the roadway. For all the project’s road works, almost 9,5 km of subsoil drains is to be installed, as well as 2,7 km of stormwater culverts. G5 and G6 construction material comes from an external quarry and crushing plant located about 30 km from site towards Carolina. Contracts Manager Mabandla Dlamini highlights the substantial local impact of the project, including the accommodation of a core labour complement of about 180 personnel in the Emakhazeni municipal district. The overall workforce managed by Concor Infrastructure, with contractors, totals closer to 700 – who are all transported 30 km daily by the local taxi network. Dlamini also points out that various subcontracts are outsourced to local small enterprises, such as drainage, stone pitching, paving, kerbing, fencing, security services and catering. Diesel is also sourced from a local fuel depot in Belfast; the project is expected to consume about 4,3 million litres of diesel in site-wide applications. Over 150 items of plant and equipment are active on the site, says site agent Sarel van der Berg, with about 40 items such as articulated dump trucks, tippers and graders from local plant hirers. 

Dams are lined in compliance with environmental regulations and best practice.

The view from the run-of-mine crusher platform between the mining area and the process plant.

33

CONSTRUCTION WORLD APRIL 2019