Engineering company Metso ND Engineering recently shipped two converters, each weighing 395 t, and as tall as an eight- storey building, from Durban harbour, to Tamatave, in Mada-gascar.
“These vessels are the largest fabricated stainless-steel pieces of equipment to leave any South African harbour. The converters measure 14,5 m in diameter and are the largest and heaviest to be built in the world,” says Metso ND MD Elvis Green.
The converters were built for minerals and metals recovery company Bateman Minerals & Metals, based in Madagascar.
Metso ND, a long-standing member of the Southern Africa Stainless Steel Development Association, was subcontracted by Bateman, in December 2007.
Engineering activities started in January 2008, and work started in February of the same year, after stainless steel mill Colum-bus Stainless Steel delivered the first material.
The sulphur dioxide converters were built for mining service company Dynatec Madagascar SA’s (DMSA’s) Ambatovy nickel project in Tamatave, Mada- gascar. Engineering and con- struction firm Noram Engineer- ing Constructors was responsible for the design and technol- ogy. The converters are major pieces of equipment required for the running of the plant.
Bateman outsourced all equipment manufactured for the project. The converters were fabricated about 6 m from the edge of Metso ND’s Bayhead facility, at a private wharf, in Durban.
“The complexity of the project and the tight delivery deadlines required extended hours of work. At the peak of the project, between 12 hours and 14 hours were worked a day,” explains Green.
Prior to the loading, the sea-bed at the harbour had to be dredged. This section of the harbour, where shipping line Jumbo’s MV Fairlane was located was too shallow for the 7,5-m draught of the loaded vessel. The coordination of the loading and transport on the site was conducted by Bateman.
The converters were designed with operating temperatures of between 420 °C and 620 °C. Each converter has a grillage beam system underneath to allow for ventilation and thermal expansion.
Once the MV Fairlane had been stabilised, the converters were lifted onto the ship using two 400-t cranes.
The first converter arrived in Tamatave after five days of sailing. The second converter arrived ten days later. Once docked, the converters were lifted from the ship onto a self-propelled motorised trailer (SPMT).
DMSA had to ensure road closures with the relevant Madagascan authorities, as the SPMT occupied the entire road.
Upon arrival at the site, a mobile 800-t crane lifted each converter from the SPMT into position on the foundations.
The converters were successfully transported from port to site, lifted and erected in less than ten hours.