Stability analysis for Dump slope and Remedial Measures Situated in Sukinda Region

Abstract

The importance of safe, properly designed and scientifically engineered slopes of the mine and dumps are well known. The benefit of an open-pit opera­tion largely depends on the use of the steepest slopes possible, which should not fail during the life of the mine. Instability in dumps generally manifests as circular failure, whereas in hard rock slopes, instability may cause portions of the slope to detach and collapse along planar surfaces.

This paper presents a geotechnical investigation of dump slope stability at a chromite opencast mine in the Sukinda region of Odisha, located between latitudes 2329562N–2330021N and longitudes 373775E–374581E. Laboratory tests conducted at the Rock & Soil Mechanics Laboratory of CSIR-CIMFR, Dhanbad determined the geotechnical parameters of the dump materials: bulk density of 16.0 kN/m³, cohesion of 85 kPa, and an internal friction angle of 28°. The average annual rainfall in the area over the past decade is 1678 mm.

Optimum dump slope design was found out by carrying out slope stability analysis.  The geo-mining condition of the mine area was considered to be in a drained state, as proper drainage arrangements were being made at both the upper portion and the lowest surface of the dump. The slope stability analysis revealed that 90-meter-high dump for this mine would remain stable with a factor of safety of 1.78. Based on the findings, CSIR-CIMFR’s slope stability team recommended preventive and remedial measures to ensure long-term dump stability and mine safety.