One of the challenges faced by rock and mineral mining operations is that the extraction and processing of these materials often involve rigorous demands on equipment, particularly in the screening stage. Mines typically rely on various types of screening media to separate and classify materials efficiently. However, the harsh conditions inherent in mining operations—such as heavy impacts from large rocks and abrasive materials—can lead to rapid wear and tear on traditional screening media like woven wire mesh. 

This results in frequent maintenance interruptions, increased operational costs, and potential safety hazards for workers. As a consequence, many mines experience significant downtime and inefficiencies, highlighting the need for more durable and effective screening solutions that can withstand the rigors of mineral processing while minimising operational disruptions.

Strategic screening upgrade resolves operational challenges

A case study illustrates how a rock and mineral mine in South Africa turned to Multotec to address the challenges it faced with its woven wire mesh screening media. The company opted for a strategic solution by transitioning to Multotec's side-tension polyurethane (PU) mats which effectively resolved the operational issues that the mine was experiencing.

The mine operates as an open-pit facility, specialising in the production of various rock and mineral products, including metallurgical materials, commercial aggregates, and lime products. These materials are essential for various industries, supplying metallurgical products to steel producers and aggregates to the construction sector.

Issues encountered with woven wire mesh

In line with common practices in the quarry industry, the mine utilised woven wire mesh screening media in its secondary sizing plant. Although this type of screening media is generally affordable and readily available, it presents several disadvantages. 

“In this case, the woven wire mesh struggled to withstand the impact and abrasion from the product stream, necessitating frequent change-outs—sometimes as often as twice a month. This led to high maintenance costs due to frequent purchases of new mesh; interruptions in production during change-outs; and increased labour hours and associated health and safety risks. It also led to the potential for entire screen decks needing replacement when small sections of the mesh failed,” says Pieter Uys, Business Development Manager at Multotec.

Finding a reliable solution

The mine sought assistance from Multotec to find a more effective solution for their screening needs. After evaluation, they decided to transition from woven wire mesh screen media to side-tension PU mats which are designed for enhanced durability and can be installed on existing vibrating screens without requiring structural modifications. 

Says Uys: “A key aspect of this solution was the custom hand-casting of PU mats to fit the exact dimensions of the vibrating screens, ensuring a precise fit and optimal performance. Additionally, these PU mats offered the advantage of easy installation in place of the traditional woven wire mesh panels, minimizing downtime during the upgrade process. Notably, this innovative approach is applicable across various operations within the sand and aggregate industry, making it a versatile and practical choice for improving screening efficiency.”

Multotec’s PU mats are also successfully utilised in other commodities globally such as Platinum Group Metals (PGMs), limestone, gold, and coal.

Measured results and cost efficiencies

Despite the initial capital expenditure associated with converting to side-tension PU mats, the mine has experienced significant improvements in screening media performance. Since their installation, the PU mats have not needed replacement for over a year; there has been a substantial reduction in maintenance, labour, and material costs; and downtime has decreased significantly, along with fewer health and safety risks related to frequent changes. Furthermore, noise levels have also been significantly reduced, which has led to improved working conditions onsite.

“The cost savings realised by moving from changing out mesh up to twice a month to not changing the PU mats at all in more than a year are favourable. There have been significant improvements in terms of downtime, labour, and material costs,” adds Uys.

As a result, the mine's total cost of ownership for the PU mats has dramatically decreased since their conversion. Additionally, Multotec's commitment to customer service is demonstrated through the assignment of a dedicated sales engineer who understands the plant’s processes, manages stock levels of replacement panels, and can quickly respond to any operational challenges.