Skeleton Coast Diamonds – SS Nujoma

Africa, Namibia
Lycopodium ADP (LADP), and sister company ADP Marine & Modular (ADP M&M), are proud of their association with the recently inaugurated SS Nujoma, the sixth and latest addition to Debmarine Namibia’s fleet, being a highly specialised and technologically advanced vessel to enable deep-water diamond exploration and sampling off the coast of Namibia

The vessel was built in Ulsteinvik in Norway by the Kleven Verft shipbuilding group, and is named after Namibia’s founding president, Dr Sam Nujoma. The 113 metre-long diesel-electric powered vessel has a displacement of 12,000 tonnes, and accommodates a crew of 80. It has a helicopter deck suitable for Sikorsky S61’s, and is equipped to remain on exploration operations for three years between port maintenance layovers.

The vessel itself was manufactured in six modules, five in Poland and one in the builder’s Norwegian shipyard. The Polish modules were transported on a barge to Kleven Verft for final assembly on the slipway.

Following its’ launch in January 2016, the vessel was sailed from Norway to Cape Town, where it was fitted out with its Mission Equipment, comprising of the sampling tool, the launch and recovery system, and the treatment plant. The treatment plant in turn comprises the following plant areas:

  • Primary plant
  • Comminution plant
  • Dense media separation plant
  • Final recovery

The treatment plant was designed by LADP / ADP M&M each of which has specialist expertise in mineral processing and modular plant design and construction, to minimize footprint, height and mass, and still provide operational flexibility in compliance with stringent ocean-going standards.

The Mission Equipment was designed and built in large modules, suitable for marine duty within a confined deck space, with a combined mass of 2,200 tonnes, in parallel with vessel construction in Norway. The modules were lifted on to the vessel using the second-largest super-lift crane in southern Africa, with the heaviest module weighing in at 220 tonnes.

A feature of the modular plant design was the ability to lift and place portions of plant from quayside, to the Vessel enabling complete fit-out and cold commissioning of the Mission Equipment within 3 months. Sea trials were then undertaken prior to hot commissioning in non-diamondiferous areas, thereby offering the opportunity to resolve issues prior to establishing the security protocols.

LADP’s process design input included the seamless processing and management of multiple samples (>5 samples), by a fully automated and intelligent system by application of a pre-designed binning philosophy and vendor-proprietary batch software. LADP also designed the automated capturing of metallurgical and processing data per sample as each is processed through the different unit processes.

"This unique and technically challenging global project has been successful in exceeding its objectives."
Michael CurtisProject Head for De Beers Marine

Of course every project has tight time, cost and quality targets so what is so different with this design? Briefly some of the design challenges were as follows:

  • Being a sampling vessel, the sample integrity is paramount and no hang-up, material entrapment or retention could be allowed between samples.
  • Furthermore unlike the rest of the fleet which are ‘winch positioned’, this vessel has dynamic positioning which facilitates the faster sampling rate that is targeted for the SS Nujoma. This required fast processing and purge cycles for each sample within each of the unit processes, which underpinned the sizing and selection of equipment.
  • With regards to control and instrumentation engineering and new to DBM and LADP was the use of ‘Dessoft’. This is an intelligent database driven software for the generation of P&IDs to facilitate the instrumentation design. Also the implementation of the ISA-88 standard for batch control, which will be used to manage and track samples, as well as record pertinent sample information through the treatment plant.
  • Layout and design challenges are obvious – footprint, height and mass had to be kept to a minimum. Ongoing weight management during the design phase alerted the LADP team to the fact that the allowable mass was being exceeded. Some clever thinking and engineering resulted in the lowering of the Final Recovery module by one floor. ADP Marine & Modular were well suited to undertaking this plant design as they have designed, built and commissioned numerous final recovery plants for the De Beers Group over the past 20 years.
  • Also important was to ensure effective integration of all treatment plant components into the platform (the vessel). In this regard detailed integration and battery limits had to be carefully managed.
  • As with any project ‘Safety in Design’ was critical. With regards a ship there are more aspects to be taken into account and stringent worldwide standards such as SOLAS (Safety Of Life At Sea) needed to be adhered to.

De Beers marine was responsible for development of the sampling tool, which was then fully integrated with the sampling system to enable collation of comprehensive sample data.

Michael Curtis, Project Head for De Beers Marine, said “This unique and technically challenging global project has been successful in exceeding its objectives. The project team understood how important the project is to our client Debmarine Namibia, and have been committed from approval of the project in April 2015 to fast track the delivery.”

Andrew Jakins, Managing Director of ADP Holdings and ADP project sponsor noted “The combined De Beers Marine and ADP teams deserve high praise for completing the immensely complex process plant scope, not without its challenges, but with all major metrics including cost, schedule, plant performance and sampling rate, sample integrity and safety being either achieved or surpassed.”

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