Diamond company De Beers' Upstream Technology business, in South Africa, has developed a next generation of advanced subsea diamond recovery crawlers, with the first unit having been installed on Debmarine Namibia's flagship vessel Benguela Gem, which operates off the coast of Namibia, after nearly four years of development.

The unit marks a significant leap in marine diamond recovery capability, De Beers Upstream Technology Next Generation Crawler project manager Rudi Agostinho says, adding that the new crawler represents a careful blend of cutting-edge automation, precision engineering and lessons from decades of operational experience.

A second unit is being assembled to take over operations during scheduled servicing of the first unit, ensuring minimal downtime.

“We have taken everything we have learned from earlier models and engineered a crawler that can operate with significantly enhanced efficiency, with greater reliability,” Agostinho says, noting that the new crawler allows the Benguela Gem to boost its effective rates by about 20%, with minimal increase to operating cost. This extra capacity means the vessel can now fully benefit from the throughput capability of its onboard treatment plant.

Debmarine Namibia – a subsidiary of Namdeb Holdings, which is a partnership between De Beers and the Namibian government – in March 2022 unveiled the $486-million custom-built Benguela Gem to increase output by about 500 000 ct/y. 

Agostinho says the next generation crawler provides a robust platform for the future of marine diamond recovery. “By combining advanced tools, adaptive systems, automation and predictive maintenance, we have delivered a crawler that will recover more material, more consistently, with less downtime – even in tougher conditions.”

The new crawler is larger than its predecessors, weighing 370 t and measuring 28 m long and 8 m high and wide. With a sweeping mining arm that covers a 21 m arc in just 25 seconds, it includes several powerful systems.

The crawler operates between 100 m and 135 m below the surface, drawing a combination of seawater, sand, gravel and diamond-bearing material through an 800-mm-diameter pipeline.

De Beers Upstream Technology mining system specialist Sebastian (Bas) van der Laer says the goal was to push engineering availability from 82% to 87%, supporting the drive for extra production.

He points to the crawler’s new track tensioning system as a key innovation, where a hydraulic tensioning system automatically adjusts as conditions change. This reduces wear, extends the life of the track chain and improves gearbox torque.