Numbara Haul Road


African Minerals Limited


Tonkolili, Sierra Leone



A new 11km haul road was required to access Numbara pit to facilitate extension of African Minerals Tonkolili iron ore mine, located in central Sierra Leone. The haul road was planned through mountainous terrain and required a significant amount of earthworks to create an acceptable and stable profile for transporting mined ore to the rail terminal at the Tonkolili site.

Quantum undertook an initial geomorphological walk through assessment of the route prior to developing a scope of intrusive works for client approval. We subsequently provided two drilling rigs and crews to undertake boreholes using dynamic sampling and rotary core methods together with an extensive trial pitting and in-situ testing exercise. Laboratory testing was undertaken at the Dawnus soils laboratory in Tonkolili.

Our assessments included earthworks materials classification, formation sub-grade assessment, slope stability assessment, excavatability assessment and material durability assessments with respect to soil erosion. We provided a comprehensive interpretive report including recommendations for borrow pit requirements, safe cut and embankment slope angles, likely blasting requirement, erosion protection measures and foundation improvement works.

All works were undertaken by our own team of experienced site engineers and operatives using our own specialist drilling and testing equipment imported from the UK.