Minerals processing specialist Multotec has designed its tailings storage facility (TSF) GV cyclones for use in extreme weather conditions and being able to withstand considerable pressure spikes, while the lightweight unit ensures ease of movement on tailings dam walls.

Tailings dams are used in the platinum-group metals (PGMs) industry, among others. An important parameter for tailings wall building is the product quality of the material that is used to construct the wall, explains Multotec applications manager Erick Herbst.

He explains that most of the product used to build the TSF wall needs to be produced at the correct product specification, which can only be achieved if the internal dimensions of the cyclone are maintained. Multotec achieves this with high wear-resistant rubber lining on the inside of the cyclone.

Herbst highlights that as the cyclone spigot wears, the quality of the product deteriorates, which can affect the quality or integrity of the outside wall of the TSF over time. Therefore, Multotec offers various options for the cyclone spigot's material of construction, as it is the highest wearing component of the cyclone.

Multotec has also incorporated various features into the design of its cyclone, including fast and tool-free spigot exchange, focussed on TSF operator’s usability.

Further, various cone angles, vortex finder, and spigot sizes ensure that Multotec can supply a custom fit solution, he explains.

Mining operations are continuously looking at methods or processes to increase minerals recovery – an endeavour which some miners pursue through milling to a finer degree to improve mineral liberation, says Multotec cyclones product specialist Ernst Bekker.

However, this in turn, changes the feed characteristics of the material used for tailings dam wall building, which can result in existing cyclones at a mining operation no longer performing optimally.

Therefore, using Multotec’s customisable GV cyclones enables mining operations to adjust the configuration of cyclones and fine-tune the performance to optimal conditions.

Further, with the assistance of experienced application engineers, cyclone modifications can be monitored to determine if additional actions are required to further optimise the cyclone units, he says.

“The impact of a non-optimal performing cyclone on the quality of material produced is not always understood,” says Bekker.

Therefore, Multotec aims to convey this message in an understandable manner that allows the operations to take corrective actions.

Easy access to information for operations, as well as providing solutions to the challenges experienced by the operations, has resulted in an increased use of Multotec’s GV cyclones by operations on both the eastern and western limbs of the
Bushveld Igneous Complex in South Africa.

Additional contributing factors to the cyclone being widely used on eastern and western limb operations is its cost effectiveness, durability, ease of use, and being easy to maintain, he notes.

Accurate Sample Reporting
Multotec sampling and magnetics product specialist Willem Slabbert explains that globally recognised sampling experts report that about 80% of installed mineral samplers do not comply to the theory of sampling in term of variances in mineral distribution and quality. From those samplers, up to 80% of total sampling errors could result from the in-plant samplers.

He adds that sample accuracy and precision level are affected by these inadequate sampler designs, with inappropriate levels of sample preparation contributing to about 15% of errors, while analysis of samples accounts for about 5% of errors.

Despite most laboratories being well regulated and compliant to applicable international standards, Slabbert says samplers are often forgotten as being a major contributor towards sampling errors.

To mitigate this, Multotec offers three-day training courses to clients that cover sampling theory, metal accounting sampling, sampling challenges, examples of correct and incorrect sampling, chrono-statistical analysis of grade results and other related matters.

Multotec also offers mechanical inspections of samplers and auditing services about sample-taking and sample preparation – measures necessary for pre-laboratory handover for analysis.

He emphasises that reporting on metal accounting throughout the PGMs value chain is a metallurgical management and metallurgical optimisation requirement, as well as a corporate governance requirement.

Accurate reporting of mineral reserves, resources and current inventories is crucial to shareholders – and potential investors on the stock exchange – as it shows when product will reach the market and revenue will be recognised.

Accurate reporting of such measures ensures that investment decisions can be made by stakeholders based on the balance sheet determined directly from metal accounting, says Slabbert.

Nonrepresentative declaration of time-constraint value could deter investor sentiment and even constitute false advertising by overstating current asset value and performance forecast, according to Slabbert.

Slabbert adds that the first step towards better environmental, social and governance practices is knowing, rather than estimating, where metal currently reports throughout the PGM value chain.

Multotec’s sample auditing service assists clients in moving towards a higher level of confidence in their metal accounting reporting, both internally to the organisation and externally to the market, Slabbert concludes.