This study examines reliable methods to monitor and manage the stability of a limestone rock slope. The surface displacement of the rock slope of Mt. Buko has been measured over the past 20 years, employing several tools and methods including automated polar system (APS), global positioning system (GPS), and leveling. The rock slope of Mt. Buko will eventually reach gigantic proportions; it will be 800 m high × 5 km long at the end of mining operations. Monitoring work was often associated with data that oscillated irregularly due to negative influences from environmental factors such as temperature, atmospheric pressure, and humidity. However, APS measurements have provided the less fluctuation data by calculating differences in slope distance. The differences in slope distance are obtained by subtracting the slope distance at a reference point in the least displaced area from those at other points. GPS measurements have provided baseline analysis data by setting the reference point in the least area. The GPS data can be converted into slope distance and compared with APS data, and the result of this has shown there are no discrepancies between two types of data. Employing APS and GPS has enabled highly accurate monitoring that produced reliable data due to cross comparisons of each data source.
