PT Freeport Indonesia (PTFI) Geo Services Division recently enhanced the slope monitoring system at Grasberg mine with the purchase of two IBIS-M radars. “Grasberg mine is one of the few mines in the world that utilises very high-technology monitoring equipment to help detect slope movements. The IBIS-M radars are top-of-the-line radars, using technology that is accurate to within approximately 0.1 mm, with coverage at some 2 km an area around 5 km square, and operating range of 10 m to 4,000 m,” explained PTFI Superintendent – Geotechnical Pit Engineering and Stability Rahadian Widiadi.
Due to the long working range, the IBIS-M radars, from Ingegneria Dei Sistemi (IDS), can be positioned at a safe distance and do not need to move during blasting. Its higher spatial resolution and faster scan time help improve timing of alarm capabilities upon detection of significant slope movements. “The operation of the radars is fully remote, done via wireless radio link, and the units have been tested in harsh mining environments and as such would be capable of handling the high rainfall, thick fog, and high altitude conditions of our Grasberg mine,” continued Superintendent – Geotechnical Dump Engineering & Stability RD Gautama.
To process the IBIS-M data, the GUARDIAN software is used. Some of its key features include real-time processing that includes automatic atmospheric corrections; processing of discontinuous data sets; and exportability of outputs to mine planning software. “This new radar technology will also support the mine expansion plan by providing better knowledge of the rock mass strength through long-term monitoring, and that same data is used to map the long-term evolution of slow-moving slopes. These results are also used to determine the mining strategy going forward, as well as the mining sequence. With this new technology we can also help reduce mining operation costs related to controlling slope stability in the pit,” said Rahadian.
“As the Grasberg pit becomes wider and deeper, it is a necessity that we use monitoring equipment that can provide long-term and long-range monitoring and area scan. With the addition of the IBIS-M radars, we can better support pit activities and provide continuous 24/7 slope coverage, thereby providing additional safety measures for those working at Grasberg,” added Technical Expert – Geo Services Mike Stawski.