What is the simplest method of building and shipping the steelwork of an entire diamond recovery plant for construction in another country? Design and build it of container-profiled elements, containing all the mechanical equipment required in an easily collapsible format, and ship them by standard container transport. This was the ingenious method devised by DRA and fabricated by Cosira International, for the steelwork of a Diamond Recovery Plant in Snap Lake, some 220 miles north of Yellowknife, North of the tree line in the Northwest Territories of Canada.

Thirty identically-sized modules were produced and fully installed in South Africa, of which eighteen formed the plant itself; while the rest were stairways and ancillary equipment. Strategic breakpoints were identified and incorporated into the piping, platework and steelwork. Welding and structural engineering had to comply with Canadian welding standards.

The plant was successfully trial-erected and cold commissioned before dispatch. As a result, this modular design allowed the plant to be efficiently transported and re-assembled at its Canadian destination with far less time, effort and cost than would normally have been the case. The design also greatly facilitated shipping and handling.

The 30m high, three-stream plant will process fines, coarse and middles material and incorporates primary and secondary x-ray, as well as Raven laser sorting systems. It also comprises a pneumatic feed system, a vacuum spillage system, dust extraction and pressurisation plant, a canning system and safe.

The project used 120 tons of square tubular steel and consisted of 100% local South African content. When the entire project is complete, it will be project developer, De Beers', first mine outside South Africa; and the first completely underground mine in Canada for De Beers. Productive life is expected at around twenty years.

Structural steel was used for many reasons. Snap Lake is located in an area so remote that road access is only available from mid-February to the end of March each year, when the road over the frozen ground and ice-covered lakes is operational. This allowed for only a short, extremely critical transport window; therefore, as much of the plant as possible had to be pre-fabricated off-site before shipping. Steel was the most suitable material for this. Steel also possesses the tensile strength, durability and design flexibility required for the hostile climatic conditions the recovery plant will experience.

A second, virtually identical plant has been constructed, shipped and re-assembled at the Victor Diamond Project, an open-pit mine situated at Attawapiskat, in Northern Ontario on the James Bay Coast. As the area boasts sixteen diamondiferous Kimberlite pipes and diamond prospecting in these areas is continuing, the market for further such South African export projects seems promising.

The project structural consulting engineer was UWR The project manager was Paul Howard of main contractors DRA, and the quantity surveyor was BJ Vorster of PCC. CVtf