Kinematic Deformation Control in Slope Design of Banded Iron Formations: A Case Study from Nkout, Cameroon

Reliable slope design is essential for ensuring the stability and safety of open pit operations, particularly in structurally complex terrains such as banded iron formations, where kinematic deformation control plays a critical role in mitigating failure risks. A kinematic slope stability assessment was performed as a key part of the geotechnical evaluation of the Nkout iron deposit in Cameroon. This paper summarizes geotechnical investigations undertaken for pit slope design, describes the notable elements of the structural and rock mass models that characterize the deposit, and discusses their impacts on slope stability and design. This study presents the geotechnical investigations undertaken to support pit slope design of the Nkout iron deposit in Cameroon. It delineates the principal attributes of the structural and rock mass models that characterize the deposit and evaluates their implications for kinematic behavior, slope stability and overall design performance. Data was collected from 13 geotechnical boreholes (GTBH's), acoustic televiewer (ATV) geophysical surveys, and geotechnical logging of diamond resource core. From the data collected, a geotechnical lithological model was created for the deposit from which kinematic and rock mass stability analysis was undertaken. The analyzed results from the field work show that the Nkout iron deposits are a steeply northerly dipping (55-70°) banded iron formation hosted within a felsic and amphibolitic waste material where the area can be split into 3 pit deposits; East, Centre, and West. This study shows that the slope heights will be governed by economical parameters not the mineralized envelope and could extend to >600 m below the current topography. In addition, the intact rock strength displays greater than 100 MPa, and the Rock mass rating (RMR) averages 65 for all materials. The slope performance will be dominated by kinematics deformation and not rock mass stability and weathering surface was determined through waste drilling extrapolated over the deposit with a depth of 45 m. The engineering description of each material located within the deposit has been made with an understanding of their physical properties. The engineering and physical understanding of the materials from laboratory testing and geotechnical logging (iRMR) has resulted in the formation of geotechnical rock mass and lithological domains. Lithological domaining produced a lithological geotechnical waste model from which cross sections were cut for limit equilibrium analysis (LEA). This paper offers valuable insights for enhancing mining operations management's understanding of kinematic deformation mechanics and provides practical knowledge on applying geotechnical pre-feasibility techniques to improve the effectiveness of open-pit mining operations.