Title: Open pit slope stability investigation of the Ouenza iron mine (NE Algeria) using rock mass description, stereographic projection, and kinematic analysis

Authors: Faouzi Mebrouk; Yacine Berrah; Rihab Hadji

Addresses: Department of Mines and Geotechnology, Laboratory of Environment, Mining Institute, Echahid Cheikh Larbi Tebessi University, 12000 Tebessa, Algeria ' Department of Mines and Geotechnology, Laboratory of Environment, Mining Institute, Echahid Cheikh Larbi Tebessi University, 12000 Tebessa, Algeria ' University Ferhat Abbas of Setif, Earth Sciences, Lab of Applied Research in Eng Geology, Geotech, Water Sc. and Environment, Setif, Algeria

Abstract: The stability of open-pit mine slopes is strongly controlled by geological structures, rock mass quality, and discontinuity orientations. This study assesses the stability of the Ouenza iron mine in northeastern Algeria through an integrated approach combining rock mass characterisation, stereographic projection, and kinematic analysis. Field investigations included discontinuity mapping and evaluation of RQD, RMR, and SMR indices. The potential for slope instability was evaluated using kinematic analysis, aided by stereographic projection, to delineate the primary failure mechanisms and assess the overall stability. Results revealed substantial heterogeneity in rock mass quality: limestone and iron-bearing units (RQD 50-98%, RMR II-III) show greater stability than yellow marl (RQD 18-65%, RMR IV). Kinematic analysis indicated planar sliding, wedge failure, and toppling, mainly in upper bench where low SMR values (1-36) denote unstable conditions. Findings link structural geology to slope stability, guiding targeted stabilisation.

Keywords: open-pit mining; slope stability; kinematic analysis; rock mass rating; RMR; slope mass rating; SMR; Ouenza mine.

DOI: 10.1504/IJMME.2026.154335

International Journal of Mining and Mineral Engineering, 2026 Vol.17 No.2, pp.97 - 124

Received: 07 Oct 2025
Accepted: 26 Nov 2025
Published online: 23 Jun 2026 *

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