Tag Archives: Howard Areington

FLSmidth high density thickeners optimise recoveries at DRC copper-cobalt mine

FLSmidth says it has delivered a thickener solution to help double production rates at one of the world’s largest copper and cobalt producers in the Democratic Republic of the Congo (DRC).

The order for the solution, which included six of FLSmidth’s high density thickeners, was placed in 2020, with delivery now completed.

The mine already had FLSmidth thickeners on site, with the company’s proposal for the mine’s expanded requirements  based on test work to confirm the characteristics of the material to be treated, according to FLSmidth General Manager Projects and Account Sales, Howard Areington.

“The tests confirmed that we could use a similar design to what we had installed on the mine some years previously,” he says. “This solution included six counter current decantation (CCD) thickeners and one pre-leach thickener, each measuring 31 m in diameter.”

These units deliver high solids underflow to optimise the recovery of dissolved metals, according to FLSmidth. In addition to the steeper floor slope, these thickeners were designed with a high torque ring gear drive design, with high tolerances that make for minimal maintenance over long periods of time, the company says.

“Our high density thickener design ensures consistently high underflow densities which allows the operator to sustain high production rates and better recoveries,” Areington says.

These CCD thickeners are manufactured from LDX2101 duplex stainless steel. This provides mechanical benefits without compromising chemical resistance, allowing the mass of each unit to be reduced, the company explained. The pre-leach thickener, which was not exposed to corrosive conditions, is constructed from carbon steel.

“We also designed and supplied five impurities removal thickeners, which are high rate thickeners, also in LDX2101 stainless steel,” Areington says. “The sizes of these units ranged from 20 to 30 m in diameter.”

Fabrication of the equipment was carried out in South Africa while accommodating the demands of the COVID-19 lockdown, which required careful planning and flexibility. With components and platework delivered to site, the welding and construction was conducted by the mine with installation assistance from FLSmidth and its agent in the region.

FLSmidth improves water balance at Mozambique coal plant with thickener tech

FLSmidth has been chosen as the preferred provider for four large bolted thickeners for a large mining customer in Mozambique.

Two of the thickeners are designed to reduce water load on the filters allowing for a drier filter product, while the other two thickeners recover water from the plant tailings.

The installation, which includes E-Volute™ feedwell technology for superior flow distribution, will contribute to achieving optimal water balance at the coal plant in Mozambique, FLSmidth says.

“The thickeners measure 45 m in diameter and will control the density of material to the belt filters, improving the plant’s output,” Howard Areington, FLSmidth’s General Manager for Projects and Account Sales in sub-Saharan Africa and the Middle East, says. “The design was based on the test work we conducted on the customer’s material, allowing us to determine the best thickener solution.”

He emphasised that a bolted thickener is quicker and safer to construct on site, saving on costs and improving quality control; both of these factors suited the project’s remote location.

“The extent of welding in the construction of normal steel thickeners typically runs into kilometres,” Areington said. “By contrast, the amount of on-site welding required by a bolted thickener can be measured in metres.”

The E-Volute feedwell technology improves flow distribution, leading to lower flocculant consumption, better settling rates and improved overflow clarity for the optimal performance of the thickener, according to FLSmidth.

Despite the COVID-19 lockdown, good progress was made on the fabrication of the thickeners in South Africa, according to FLSmidth Project Manager, Kevin Kockott. This has been managed by leveraging FLSmidth’s global resources and the design teams’ ability to work remotely.

“Our local South African office collaborated closely with our engineering hub in Salt Lake City in the United States, ensuring that our engineering work on the project was able to continue without interruption,” Kockott said.

FLSmidth has been involved with this project for almost a decade and has provided a significant portion of the coal preparation equipment. To date, this has included reflux classifier technology, pumps, screens and feeders.