The iDredge commissioned by Africa Resources and designed and fabricated by Imilingo Mineral Processing has produced 14,1 carats from 1 200 kg of alluvial/gravel deposits in the Kasai River in the first test run.
Thomas Häggkvist, the CEO of Africa Resources AB, approached Imilingo Mineral Processing in October 2016 for a possible solution to the cumbersome and hazardous diving conditions involved in alluvial diamond recovery.
“Modern mining techniques and sorting technology has been severely lacking in alluvial diamond mining and the iDredge has certainly delivered in injecting some much needed technological advancement in the industry,” comments Thomas. Technology to change mining game Jaco Prinsloo, MD of Imilingo, worked with a team of engineers to design and fabricate the iDredge.
Jaco asserts the ingenuity of their design is transforming digital automation in the diamond mining game. “The vessel consists of a floating platform
connected to two pontoons. A Dragflow 60 Kw submersible pump with high-depth compensators provides suction and allows particles up to
60mm in size to be pumped through the 150 NB pipe. An onboard rotatable crane submerges the pump and is there to make the pump accessible
for maintenance purposes.
“A 150 KVA diesel generator supplies power for the iDredge and the mined material is fed onto a double-deck vibrating screen. Both generator and
screen remain on the riverbank. The iDredge has the unique advantage of being collapsible for transport, making it feasible to reach remote destinations.” The iDredge began the journey from Imilingo’s
Centurion fabrication facility in December 2017.
Road transport to the port at Durban took a week and after 17 days at sea, the two 40ft and two 20ft containers arrived at the port of Matadi on the
West Coast of the DRC.
“Much of the infrastructure in the DRC, especially the road network, is extremely eroded which necessitated a change in the site where the iDredge
would be used,” Jaco says.
A technical team from Imilingo Mineral Processing accompanied the mining team on their journey to help assemble the iDredge. The machine was assembled in an excavation next to the river and the same excavator did duty as a crane for some of the heavier components.
When assembled, the excavation was flooded and the iDredge entered the river. Cables were linked to the opposite shore to winch the vessel into position in the centre of the river. “Rivers in the DRC flow very fast and we had made sure that two sturdy trees on either side of the river acted as anchors for the iDredge cables,” Jaco explains.
After the Imilingo commissioning team left, the local site team continued operations and cleared the river bed of sand overburden before reaching the diamond gravel. The first diamond gravel was pumped on 29 August 2018 and then washed to recover the company’s first diamonds.
The test run shows great potential for Africa Resources’ operations in Tshikapa and all parties are immensely optimistic at the prospect
of diamond recovery in the area. “The test run showed bags
of promise with 14,1 carats from 1 200 kg which would equate to
1 175 cpht based on the isolated test,” Jaco concludes.