Project Overview

In 2010 Dawnus commenced a series of projects as part of the infrastructure works at Tonkolili Iron Ore Mine in central Sierra Leone, for client Africa Minerals Ltd. Since starting on site we have been engaged on numerous projects and support tasks. 

These works include construction of mine haul roads, foundations and related infrastructure for major processing facilities and crushing plant, process waste storage weir and a tailings dam. These works have included 1,100,000m3 of earthworks. 

Infrastructure, foundations and enabling works we carried out at the mine included: 

  • Foundations for the main process plant that will produce 1,000,000 tonnes of iron ore per annum. 16,000m3 of structural concrete was completed in 6 months.
  • Primary crusher foundations (2500m3 concrete) and walls (reinforced earth 70,000m3 with concrete facing panels 1250 precast on site) as well as traditional concrete retaining walls.
  • Precast foundations for an overland conveyor from mine plateau to process plant 2.5km away.
  • Various foundations for the conveyor system within the process plant area and train loading area.
  • 25km of new haul roads, including 10km of extra wide road able to accommodate CAT 777 dump trucks in mountainous terrain.
  • Numerous culverts and stream diversions for the above lengths of road and standing areas.
  • Logistics infrastructure, including workshops, accommodation, offices and mess kitchens.
  • Installation of plant, concrete batching and concrete pumping equipment. 

Not all of the specified materials are available in Sierra Leone, and Dawnus met the challenge of procuring steel trusses, roof coverings, finishes and fit-out materials from overseas. All aggregates for concrete, filter media to dams, mass rock fill and rail ballast required at Tonkolili were produced by the on-site Wendugu Quarry. 

Our onsite laboratory undertook testing and analysis of all construction materials, products supplied, produced and incorporated into the works. 

We employed full design, ground investigation and geotechnical support teams to assist in commissioning all of the works. 

On all our projects in West Africa we have employed local people and provided training and development in a range of construction disciplines, to European standards.

Project Gallery


African Minerals


Sierra Leone

Project Value


Contract Period

88 weeks