As West Africa’s mining sector continues its path of growth, Multotec has been steadily increasing its installed base of solutions in the field, including mill liners and sampling equipment.
With a local branch presence in Ghana, the South African-based mineral processing equipment leader has been investing in the region for decades, developing its understanding of local challenges and applying practical solutions. In the past year, Multotec has won mill lining contracts at a number of mines and is seeing steady growth in wet and dry sampling installations.
According to Sam Hearn, global sales and business development manager at Multotec Rubber, this includes contracts to supply mill linings for ball mills at gold mining operations in Mali and Burkina Faso, where the harsh rock characteristics of the Birimian formation make for challenging comminution conditions.
“Following a detailed on-site audit, we design responses to issues that our customers face in their milling circuits,” says Hearn. “Using our sophisticated software, we are able to run simulations and finetune the mill lining solution to assist in optimising process efficiency and productivity.”
As an example, Hearn cites an instance where the rapid wear on a competitor’s mill lining was causing unacceptable downtime. Multotec Rubber was able to recommend its premium-compound rubber linings which can deal with the high impact and abrasion in this application and as a result secured the order to replace the mill liner.
In another intervention, the company has resolved a mine’s challenge with grate-blinding caused by the hardness of the rock. These new mill linings are for relatively large mills and measure up to 6.1 metre in diameter and are 9.2 metres long.
Matodzi Ramalamula, Multotec Rubber area sales manager, says that having a physical presence in the region is important for the company. “The mill liner installation team, based at our Ghana office, serves West Africa and is well-trained and experienced – an indication of Multotec’s investment in our people and skills.”
Ramalamula highlights the expertise and technology that is necessary to deliver performance improvements in a customer’s mill. It includes data gathering on all relevant operating parameters of the equipment as well as understanding the customer’s priorities before developing and proposing a solution.
“Once we have the necessary information, our technical team review this and will produce a design that addresses the important challenges,” he says. “The variables and priorities may range from throughput volumes and fineness of grind, to liner life and power usage.”
Once installed, the solution is monitored on an ongoing basis. Multotec Rubber uses in-house technology tools like its MultoScan hardware and software to report on liner profiles, as well as its HawkEye software to analyse results. In collaboration with Multotec technical personnel, customers can keep track of liner wear, which allows maintenance plans to be better aligned with existing plant shutdown schedules. This also allows leaner stockholding of spares, leading to significant cashflow savings for the mine.
Multotec Process Equipment’s wet and dry sampling solutions are also playing an increasingly valuable role in West African mining operations. Well-known in the region’s mining fraternity for over two decades, the Multotec slurry samplers are the equipment of choice in most gold mines there, according to Willem Slabbert, process manager at Multotec Process Equipment.
Customers include not just the well-known major mineral producers but many of the smaller entrants to the area’s burgeoning industry.
“West Africa is a growing market for Multotec samplers, with many of our orders repeat business,” says Slabbert. “In addition to supplying sampling units on mine sites, there is also demand for applications such as ship-loading conveyors involving bulk materials being loaded into vessels for export.”
Slabbert highlights that gold mines use the slurry samplers mainly for gold metal accounting and reconciliation in their process plants, while dry samplers enable compliance checking of bulk commodities between a mine and process plant as well as saleable product grades between a mine and its customer.
The company has, for many years, supplied sampling technology to a major bauxite producer in Guinea, for instance, and is set to install two more sampling plants for another bauxite company in that country.
“Bias-free sampling is a non-negotiable for any mining operation, and we have a comprehensive range of samplers, wet or dry, that we tailor for applications,” he says. “Many of the orders we receive are for brownfields operations, where placement and dimensions must suit the existing plant constraints. Our skilled technical personnel has the necessary experience and capability to understand the environment and design the solution accordingly.”
“This means accommodating variables like throughput rates and slurry densities, including accounting for grade variability from various mine sources feeding a single processing plant in many of the West African deposits.”
In the region, commodities like iron ore and heavy minerals have also been common applications. Slabbert emphasises the importance of ensuring representative samples – a combination of reproducibility and accuracy – in the operation of the samplers.
“The fewer operator interventions there are, the more precise the results from the automated, mechanical samplers are likely to be,” he says. “Our design therefore prioritises reliability, with features such as hard-wired electricals, automated wash-water systems and ergonomic composite sample volumes.”
Such has been the success of the Multotec samplers that they are now present on more than 30 sites around West Africa. Support from Multotec’s Ghana branch reaches countries including Burkina Faso, Guinea, Guinea-Bissau, Liberia, Mali and Sierra Leone.