Two new conceptual screening solutions suited to the local sector were floated at this year’s Institute of Quarrying Southern Africa Conference and Exhibition – held on April 16 and 17 at the Elangeni Hotel in Durban, KwaZulu-Natal – by international minerals processing specialist Multotec.

The company introduced its end-tension polyurethane (PU) mat and side-tension rubber mat, both of which are still in the testing phase, to demonstrate its advancement of screening efficiency. Both mats are designed to improve screening efficiency, reduce recirculating load and decrease the need for manual intervention, ultimately lowering operational costs.

The mats offer an alternative to woven wire screening systems and perforated metal plates.

“Both the mats were well received by existing clients and new guests,” says Multotec consumables West regional sales manager Pieter Uys.

Consequently, Multotec has received numerous expressions of interest, as clients aim to assess the economic and practical viability of transitioning from a woven wire screening system to the new mat systems.

Uys says the mats require no additional infrastructure, as they represent a like-for-like alternative to woven wire screening systems, with the PU end-tension mat tensioning from top to bottom and the side tension rubber mats tensioning from side to side.

The side tension rubber mat is installed the same way as a traditional woven wire mesh and is available in perforations ranging from 4 mm to 40 mm, and in thicknesses from 6 mm to 12 mm, depending on the application or screening medium.

“The PU end tension mat has shown excellent results in limestone quarries during the initial phase of testing, improving underflow tonnage and reducing recirculating load,” says Uys, adding that the mats have been notably effective in addressing blinding in tertiary screening applications.

Overcoming Challenges

Multotec’s mats address a major challenge faced by many quarries, says Uys, noting that blinding in tertiary screening applications – particularly when handling wet, sticky or fine materials – can clog the screen mesh and block the apertures.

While some solutions – such as soft rubber panels, high-flow panels, vibroplast panels and flapper panels – have been available to the market, the company has made notable advancements in developing side tension solutions designed to replace woven wire mesh without the need for costly screening deck conversions to accommodate new solutions.

“Although these screens have become increasingly common, they still represent a considerable capital investment for quarries.”

They are engineered to be dynamic during operation, vibrating in sync with a screen’s mechanics to keep the surface clean, unlike the more commonly used rigid woven wire mesh, adds Uys.

A key advantage of the mats is their extended life span, as they can be used for anywhere between three to six times longer than steel screens before having to be replaced.

Further, PU and rubber surfaces are smoother and generate less friction than woven wire mesh, facilitating free product flow and reducing wear and tear, he claims.

From a health and safety standpoint, the mats are made of smooth materials with fewer sharp edges, thereby decreasing injury risks during installation and maintenance, while significantly reducing noise levels, adds Uys.

While it is finalising testing, Multotec is also progressing with the development of a third new screening offering for the quarrying sector – the side tension MBV mat. Testing of the product is in its second phase of evaluation, having already demonstrated strong performance in reducing blinding.

The modular design of the side tension MBV mats is cast in 305 mm units that span from side plate to side plate.

This modularity allows for targeted replacement in case of damage, reducing downtime compared to traditional screening media, which may require complete replacement or patching, he explains.

“Overall, these products improve operational efficiency, lower labour costs, enhance safety and provide more consistent screening performance, ultimately leading to increased plant uptime and reduced maintenance requirements.”