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In a mining operation, maintaining safe and cost-effective slope geometries is critical. Monitoring has often proven to be a valuable method in dealing with potential slope instability when design analysis and engineering judgment have dictated conservative and usually more expensive problem solutions. Unexpected pit wall collapses could have a significant impact on the safety and profitability of an openpit operation. As a result, a well-planned and executed monitoring programme can permit operation with a lower theoretical margin of safety. Monitoring provides an important check on design parameters and can measure the effects of corrective actions, which lead to increased significant production and reduced economic losses. Often, early warning of impending failure can be established. In this paper, a slope failure of a pit wall stability on the north side of a limestone mine which leads to stopping the workings by the regulatory body was studied. A comprehensive slope monitoring strategy has been implemented to improve safety and mine more economically using different slope monitoring techniques like visual inspection, prism monitoring, piezometer and wireline extensometers are also used to predict the instability of the failure area of a limestone mine. All of these monitoring tools offer primary monitoring, which is used to determine the riskiness of a failure area or zone. It gives early warning of further failure or instability if the slope is detected in challenging conditions. Today’s mining regulations place a strong emphasis on the proactive identification and mitigation of risks to employees and the operation. This paper focuses on reducing operational and safety risks through an approved monitoring programme. Based on slope monitoring results of the failure area, remedial measures to improve the stability of the workings are presented for a limestone mine. [ABSTRACT FROM AUTHOR]

The stability of rock slopes in an opencast limestone mine throughout the mining process was investigated using the limit equilibrium approach (SlopeW). The optimal excavation method with a substantially steeper slope angle of 450 rather than 350 was successfully accomplished at the critical geological section of the pit slope under numerous geologically disturbed area such as joints, faults and folds on a geotechnical basis in order to ensure adequate stability against any failure while working in the mine. The primary objective of this paper is to use the limit equilibrium approach in the SlopeW programme to predict the slope’s safety factor and critical failure surface geometry due to the imposed of a surcharge loading of dump on top of the open pit slope for a 110m deep rock cut in the limestone mine. Geotechnical studies covering field geological mapping, laboratory experiments on rock samples cored from exploration drilling and different rock blocks retrieved straight from the mine were used to determine the physico-mechanical characteristics of the rock components, and numerical analysis using limit equilibrium technique (SlopeW) was carried out. It is also recommended that no activity or construction take place on the top of the pit slope crest in order to prevent further slope failures in old scheme and shifting dump 25m away from the top of pit slope for future safe workings in the mine. [ABSTRACT FROM AUTHOR]