Afrimat Glen Douglas mine achieves significant cost savings with Multotec’s side-tension PU mats at Gauteng quarry

To address the challenges faced by Afrimat Glen Douglas Dolomite Mine in dealing with its woven wire mesh screening media, the company opted for a solution by transitioning to Multotec’s side-tension polyurethane (PU) mats. This strategic shift proved highly successful in overcoming the challenges encountered at the mine.

Client background

Situated in the southern region of Gauteng, the Afrimat Glen Douglas Dolomite Mine operates as an open pit, specialising in the production of metallurgical dolomite, commercial aggregates, and dolomitic lime products. The quarry has been operational since 1954 and has remaining dolomite reserves estimated to last between 30 and 40 years. In 2010, the operation was acquired by Afrimat, a mid-tier mining and materials company. The Glen Douglas mine supplies metallurgical dolomite to steel producers, commercial aggregates to concrete producers and the construction industry, as well as dolimitic lime to the agricultural sector. The Glen Douglas mine provides Afrimat with a strong presence in Gauteng and a strategic ability to service clients based in the western, southwestern and southern parts of the province.

The challenge

As is common within the quarry industry in South Africa, the Afrimat Glen Douglas Dolomite Mine used woven wire mesh screening media in its -40mm secondary sizing plant. This is the screening media commonly used by quarry operators, mainly because it is affordable and readily available. However, there are several disadvantages to using woven wire mesh screening media and, in the case of the Glen Douglas Dolomite Mine, the woven wire mesh was not coping with the impact and abrasion of the product stream. As a result, the mesh had to be changed out sometimes as often as twice a month. This resulted in high maintenance costs, as new mesh had to be purchased, and production had to be interrupted to do the change-out. Additionally, it led to extremely high labour hours and increased associated health and safety risks due to the frequent change-outs. Compounding the mine’s challenges was the fact that when a small section of the mesh would fail, it could result in the replacement of the entire screen deck. Attempts to patch the damaged section would typically result in blinding (when aperture holes become clogged up with fines) and pegging (when a particular piece of product, usually close to the cut size, gets stuck in the woven wire mesh).

The solution

The Afrimat Glen Douglas Dolomite Mine approached Multotec for a possible solution and agreed to change from woven wire mesh screen media to side-tension PU mats. These mats are more durable and could be fitted to the mine’s existing vibrating screens in place of the woven wire mesh panels. This meant that no structural modifications were needed on the vibrating screen. Multotec was able to hand-cast the PU mats to the exact dimensions of the vibrating screen and fit them in the same manner as the woven wire mesh. The solution is 100% transferable to any operation within the sand and aggregate industry and Multotec’s PU mats are used in many other commodities such as Platinum Group Metals (PGMs), limestone, gold and coal across the globe with great success.

The result

Despite the initial capital expenditure required for the conversion to the more expensive side-tension PU mats, the Glen Douglas Dolomite Mine has seen a favourable improvement in the performance of its screening media. Since the installation, the PU mats have performed exceptionally well, with the vastly more durable mats not having to be changed out for over a year. The mine has thus seen a significant reduction in the costs of maintenance, labour and materials, as well as a reduction in downtime and fewer health and safety risks associated with frequent screen media changes. This also means that the mine’s cost of ownership of the PU mats has decreased dramatically since the conversion in October 2022. Additionally, with Multotec being a global company with a very strong local footprint, the Glen Douglas Dolomite Mine has been assigned a dedicated sales engineer to provide aftermarket sales service. The sales engineer has a good understanding of the plant’s processes, manage stock level of replacement panels and is able to respond to any challenges or changing conditions. As such, Multotec can provide solutions and services throughout the lifespan of the mine.

Quotes

“The benefits speak for themselves. The extended lifespan of the PU mats, less downtime, less production loss and lower labour costs have resulted in a massive saving for the mine.” - Theo Ferreira, Mine Manager at Afrimat Glen Douglas Mine

“The cost savings that the Glen Douglas Dolomite Mine 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.” - Pieter Uys, Business Development Manager at Multotec