Geotechnical Analyses of Mining Waste Rocks from the Central-Western Part of Côte D’Ivoire: Use as Road Embankment

Abstract

Materials based on mining waste are increasingly used in road engineering and building construction. These mining wastes, produced in large quantities during ore mining, pollute the environment. How can this waste be used in road surfacing and construction? This study was conducted to answer this question. It aims to analyze the geotechnical characterization of mining wastes generated by gold mining operations, particularly those in Hiré, in the central-west of Côte d’Ivoire, with a view to using them in the construction of embankments for road engineering structures. Experimental laboratory tests were conducted on the mining waste rocks. These tests were based on particle size analysis, Atterberg limits, and the physical behavior of the materials. Through this analysis, the experimental results made it possible to identify these mining wastes, to determine their hydrological nature, and the quality of the wastes to carry a load (traffic). The results of this analysis reveal that these waste rocks belong to the A-1b soil category. The uniformity coefficients (Cu equal to 12.4) and curvature coefficients (Cc equal to 1.29) show that they have a semi-spread, non-uniform and well-graded grain size. The plasticity index (PI) is 5%. The dry density of these waste rocks is 2.17 g/cm 3 for an optimal water content of 8.6%. The 95% CBR values of the Modified Optimum Proctor after 4 days of immersion in water are 39.6, a value greater than 30. They constitute the S5 soils class, which are lateritic gravelly type with a CBR greater than thirty. They are usable as road bases. These Hiré mine waste rocks can be considered as potential materials for the construction of road embankments with good rigid internal stability.