Tag Archives: Faan Bornman

Multotec spirals helping assess heavy minerals potential in Cameroon

Comminution of minerals, Energy minerals, Mineral processing, Mineral project development, Mining equipment, Mining services, , , , , , , ,

Exploring for heavy minerals in Cameroon, a multinational mining company is gaining valuable results and insights through the use of an on-site pilot plant from South Africa-based process equipment leader Multotec.

The pilot plant was designed and assembled at Multotec’s extensive design, manufacturing and testing facilities at Spartan near Johannesburg, South Africa, and shipped to the remote site in central Africa last year. The containerised plant includes a range of Multotec’s own equipment including screen panels, cyclone rig and spiral rig.

According to Faan Bornman, Technology Manager: Research and Development at Multotec’s Technology Division, drill samples from the prospect area are passed over the screen to remove oversized material, with undersize going into a sump to be mixed with water to the correct density. The undersize material reports to the cyclone for desliming – the removal of very fine particles – delivering an underflow with an optimal size range of between 38 microns and 1 mm. This is fed to the spiral rig for concentration, with the spiral delivering a concentrate, middlings and tailings. The process allows the project to assess its economic heavy minerals portion, which is concentrated towards the inner section of the spiral.

“Multotec’s HX5 and 117HM spirals were employed to suit the customer’s requirement, with the new 117HM spiral showing great recovery in mineral sands,” Bornman says. “With the HX5 handling up to 5.5 t/h and the 117HM 2.3 t/h, these spirals also offer different recoveries and grade in the various heavy minerals.”

The equipment in this pilot plant is vital to achieving an accurate assessment of the deposit’s viability, but the results also give the customer important insights into how the full-scale plant should be designed if exploration proves results provide positive, according to Multotec.

“To ensure that the customer receives optimal value from the pilot plant, we sent a process engineer to site to commission the system,” Bornman says. “During the several weeks that he spent there, he also conducted training with local staff on how to run and maintain the plant.”

Multotec’s SX10 low density spiral opens up coal separation options

Coal technology, Mineral processing, Mining equipment, Mining services, Steel and iron ore, , , , , , , ,

Multotec Gravity Division says its new SX10 low density spiral further extends the benefits this innovation offers in fine coal beneficiation, with the technology able to produce both thermal and coking coal on one spiral.

The Multotec SX10 low density spiral’s reduced cut point of 1.55 g/cm3 delivers considerable advantages over the cut points of between 1.6 and 1.8 g/cm3 typically achieved in the coal industry today, according to Multotec Technology Manager, Faan Bornman.

The result, he says, is cleaner coal with less waste being achieved in a single stage. This helps achieve savings on capital costs as no further spiral stages are required for cleaning down the line.

“The approach taken with the Multotec SX10 spiral is to remove the gangue, or mineral containing particles, from the trough in two off-takes,” Multotec said.

The first off-take removes ash, opening up the available separation surface of the spiral and allowing the remaining material to separate more easily. This separates clean coal from less-clean coal.

“The low density spiral is essentially a primary and secondary stage on one centre column,” Bornman said. “Rejects are discarded into the centre column and the remaining product is re-pulped before being sent to a secondary off-take.”

Facilitating the two off-takes is a longer spiral on the Multotec SX10. This increases the residence time and gives the particles sufficient time to separate, according to the company.

Depending on the setting of the product box splitters, this new spiral has the ability to produce both thermal coal and coking coal on one spiral, Multotec claimed. Bornman said this was proven through test work done in the US where the two offtakes enable the removal of most of the gangue leaving a middlings and cleaner coal products to be collected at the dart splitters.

Experimental work was carried out using coal from two South Africa collieries as well as doing site test work in the US. Promising results were obtained leading to the first order for Multotec SX10 spirals from a North America-based mine, it said.