Durable screen media that can match your shutdown cycle

The efficiency challenge

With a resource base of 7.5 million ounces of gold and 67 million ounces of silver, Martabe Mine is one of the largest gold mines in the world. Located in North Sumatra, Indonesia and managed by PT Agincourt Resources, the mine commenced operations in July 2012. It has an annual operating capacity of 4.5 Mt of processed ore, 260,000 ounces of gold and 2.1 million ounces of silver.

Every seven weeks, a shutdown of the SAG Mill was scheduled to assess and maintain the steel mill liners and screen media. Yet the metallurgy team at the mine observed that the feed-end blank panel’s mean time to failure was a maximum of four weeks. Depending on the mill discharge grate wear, sometimes only three weeks wear-life was achieved. This meant, even with the original seven-week shutdown frequency, the SAG Mill faced unplanned downtime and production loss to allow the feed-end blank panels to be changed.

However, the mine’s ultimate goal was to extend the shutdown to 16 weeks. Therefore, changes needed to be made.

The sustainable solution

The Martabe Mine turned to FLSmidth for help as our solution was not only easy to install and cost effective, but it is also expected to provide better performance and higher throughput in 16-plus weeks of wear. FLSmidth Ludowici offers the most comprehensive, reliable and innovative range of screen surface media in the industry to suit almost every application.

At the Martabe Mine, the mill discharge is fed onto an FLSmidth BRU 3.0 x 7.3 Horizontal Screen. The screen media installed was the FLSmidth LUDODECK P2 modular system and the feed-end had three rows of blank panels for the mill discharge chute to feed onto. The performance of the aperture panels did not need attention. There was no pegging of apertures and wear on the panels, meant the feed-end screen decks only required changing twice a year and the discharge screen decks just once a year.

Wear measurements at seven weeks

The solution was delivered in two stages and involved trials and discussions that spanned a number of months. The Martabe Mine’s screen media’s wear was reduced by combining a section of already installed LUDODECK P2 modular screen panels with removable rubber wear plates.

This process firstly involved increasing the panel’s thickness from 46 mm to 60 mm. Then, steel-backed rubber wear pads were bolted to the screen panels. This increased the overall thickness to 86 mm and meant the blank screen panel did not see any wear, allowing for reuse after every shutdown.

The installation of the FLSmidth solution did not change the Martabe Mine’s original fixing method. Therefore, the panels were fitted by the mine crew on time and without any reported injuries. In addition, future replacements can be assembled offline and fitted quickly when required.

The metallurgy team inspected the feed-end blank panels after two weeks of use and found the panels in very good condition. The panels were inspected again at seven weeks of use and the wear was considered very satisfactory.

Feed end panel wear prediction

*With a measured wear rate of 0.27 mm per day as at 17/3/2018 the metallurgy team is confident the panels will last beyond the 16-week campaign.