In June 2015, following successful delivery of the Enabling Works contract for Mount Coffee Hydropower Plant, Dawnus was awarded the contract for the Main Civils Works.
These works included the reconstruction and rehabilitation of the power house, intake, spillway, dams, tailrace structures, roads and infrastructure, and miscellaneous works:
Rehabilitation of the Power House
- Substructure – four reinforced concrete monoliths comprising multi levels (draft tube, scroll case, turbine floor, machine hall).
- Superstructure – reinforced concrete frame and roof (67m x 16m plan, 14m high)
- Structural concrete repairs and improvements to accommodate four new turbines and associated generators and equipment, with a total 84MW capacity.
- Cladding to roof and elevations.
- M&E installation, including HVAC system, small power, fire alarms, and water systems retro-fitted.
- 100m wide reinforced concrete, six-bay intake structure.
- Underpinning, earthwork remedials, crest elevation increase (raise deck, upstream wall, gate towers), concrete repairs, reconstruction of service buildings.
- 150m reinforced concrete Ogee Spillway structure – 10 bays supporting radials gates.
- Remove deck, raise piers and upstream wall, and reinstall deck.
- Construction of main dam and three Forebay dams. 2,500m Laterite construction with internal drain system, erosion protection on flanks, and access road along axis of dam.
- Re-profiling and restoration of three existing dams.
- Breached dam reconstruction – 295,000m3 of materials, 26m in height.
Dawnus worked closely with other specialist contractors who include Voith who were responsible for the turbines and electrical and mechanical installation, Andritz who were building the gates and other hydraulic steel structures, Eltel for the transmission lines and NCC for the substations. The catchment area covers an area of 20,000km2.