Accurate sampling is key to the success of the valuable bauxite industry in the west African country of Guinea, and Multotec Process Equipment’s high-precision sampling equipment is playing its part.

Multotec has recently provided two tariff sampling plants to a major bauxite producer, including what is possibly one of the largest hammer samplers in the world. One of the plants is located at the bauxite mining operation itself, while the other is at the export facility where the high-grade bauxite is loaded onto ships.

According to Willem Slabbert, sampling and magnetics specialist at Multotec Process Equipment, the samplers serve a vital role in representatively measuring the quality of the material mined and then exported, as well as its physical characteristics.

“At the mine, the sampling plant gives the mining company and their third-party mining contractor a scientific basis on which to check compliance with their contractual requirements,” says Slabbert. “Similarly, the plant at the export facility assures the end-customer of the quality of bauxite they are purchasing.”

The solution designed for this specific application includes hammer samplers, double-roll crushers, rotating plate dividers, feeder conveyors and barcoded carousels to link the sampling plant’s hourly performance to the indexed samples produced. There is also protection equipment – a moisture analyser, overbelt magnet and metal detector – and inter-sampling plant conveyors.

“The plants were designed as a holistic solution, to deliver measurements in line with the international standard ISO8685 – ensuring that both sides of a contractual agreement can feel confident in the results,” he says. “They are also fully automatic and PLC-controlled for maximum efficiency.”

He highlights that the sampling and materials handling solution was based on extensive test work carried out at Multotec’s well-equipped facilities in Spartan near Johannesburg. Crusher tests were also done on the specific bauxite, which comprised a substrate material with very hard embedded nodules.

“We identified custom-designed, heavy-duty, double-roll crushers as the optimal solution to deal with the extreme hardness of the nodules in the material,” he says. “The abrasiveness and stickiness of the Guinean bauxite also required low-friction liners to be designed into each plant.”

Supporting its installations with highly experienced technicians, Multotec also has a West African branch in Ghana which sources local components for customers. The branch has capacity to deliver support and maintenance services as well as provide training to local operators, in English and in French.

Multotec Process Equipment has plenty of experience in sampling bauxite in Guinea, says Slabbert, with another sampling plant installed two decades ago for another bauxite producer.