A case study presented in GeoSolutions Asia- Australia summite, Bali- Indonesia: 03-Jun-2026- Organised by Orica Digital Solutions- Ground Probe
T J-RESOURCES BOLAANG MONGONDOW
BAKAN SITE, NORTH SULAWESI
Slope failures in weak argillic materials present significant challenges for open-pit mining operations because such formations are often difficult to identify accurately through conventional geological models. A recent case from the Main Ridge Pit of PT J-Resources Bolaang Mongondow (JRBM), Bakan Site, North Sulawesi, Indonesia, demonstrates how real-time radar monitoring can provide critical information for managing geotechnical risks and ensuring operational safety.
This case study presents a back-analysis of slope failures in argillic material that occurred at the Pit Main Ridge – JRBM
Bakan Site using SSR605-XT Radar Monitoring Data from November 20th, 2024, to December 12th, 2024.
The argillic material slopes at the JRBM open-pit gold mine are considered weak and susceptible to slope failures if the
Bench Face Angle (BFA) does not conform to geotechnical recommendations. This formation is difficult to detect in
geological wireframe models, so its presence must be monitored in real time to avoid operational risks in mining. In this
case, besides argillic material, failure was also caused by the presence of a fault geological structure that created a
groundwater flow path, thereby increasing the pore water pressure on the failure wall.
Based on real-time monitoring of the SSR 605-XT Radar over 1 month, which monitored argillic material formations in the
Main Ridge Pit Entrance Access area (JRBM Main Access), the results provided numerous benefits for decision-making
during mining operations, including:
- Determine whether the access road is passable or must be blocked.
- Determine when argillic slope remediation can be safely carried out.
- Make decisions about alternative routes to avoid future operational disruptions.
- Ensuring the slope is stable so the road can be reused
The instability area was monitored by the SSR605XT Radar with the following results:
- Consistent linear deformation pattern from November 27th to December 3rd, 2024 -On December 12th, the deformation pattern began to show progressive deformation, starting at 4:40 a.m.
- The Geotech Team then analysed the failure prediction data and evacuated the area from 11:40 a.m. until the failure occurred at 12:40 p.m
During the initial monitoring period from 20 to 26 November 2024, no significant deformation was observed. However, beginning on 27 November, the radar detected a consistent linear deformation trend that persisted until 3 December. Such deformation behaviour indicated gradual movement within the slope mass but did not immediately suggest impending failure.
On 12 December 2024, the deformation characteristics changed markedly. At approximately 4:40 a.m., the slope began exhibiting progressive deformation, indicating acceleration towards failure. Continuous analysis of the radar data by the geotechnical team enabled the application of inverse velocity forecasting techniques. The intersection of the inverse velocity trend with the time axis predicted a failure occurrence at approximately 12:40 p.m. Remarkably, the actual slope collapse occurred at the predicted time, demonstrating the effectiveness of the SSR605-XT system in forecasting failure events.
Based on the radar observations and failure predictions, the geotechnical and safety teams initiated proactive risk management measures. By 10:00 a.m., the main access road was blocked and traffic was diverted to alternative routes. Subsequently, the potentially affected area was evacuated from 11:40 a.m., approximately one hour before the actual failure occurred at 12:40 p.m. These timely actions ensured that no personnel or equipment were exposed to the failure event.
- Geotech Team then analysed the failure prediction data and evacuated the area from 11:40 a.m. until
the failure occurred at 12:40 p.m. - The predicted failure time is determined based on
the Inverse Velocity vs Deformation crossing, so
that the result is obtained at 12:40 p.m., and the
result is in accordance with the actual failure time
in the field. - At 10.00, the Geotech Team and Safety Team blocked the main access and diverted road access
The case highlights several important benefits of continuous radar monitoring in open-pit mines. First, it provided reliable information for determining whether the haul road remained safe for use or required closure. Second, it assisted in planning and executing slope remediation activities under safe conditions. Third, the monitoring data supported strategic decisions regarding alternative access routes to minimize operational disruptions. Finally, the system provided confidence in assessing post-failure stability and determining when mining operations could safely resume.
This case study demonstrates that the integration of high-resolution slope radar monitoring with geotechnical interpretation and timely operational response can significantly enhance mine safety and reduce production losses. In geologically complex environments characterized by weak argillic materials and groundwater influences, the SSR605-XT radar proved to be an effective tool for detecting accelerating deformation and accurately forecasting failure, thereby enabling proactive rather than reactive slope management.
Ref: GeoSolutions- Asia-Australia Summit- 2026, Bali-Indonesia, Organised by Ground Probe- Orica Digital Solution.