Malange Province with new infrastructure, the Quizenga Dam | NOV Group

NOV Engenharia e Construções concluded, in mid-July 2022, the contract for the Quizenga Dam, an infrastructure integrated in the global project of the Quizenga Agricultural Pole, in the province of Malange, in Angola.

The work, which started in March 2021, involved several works and large volumes, namely: carrying out clearing and stripping (60,000 m3), excavation and landfill of the cut-off (57,000 m3), landfill of the dam body (260,000 m3), injection curtain (1 500 ml), anchoring/nailing’s (270 ml), sand filter (25 000 m3), riprap (Rip-Rap) (15 000 m3) and transitions (7 000 m3), concrete in catchment, bottom discharge and surface discharge (1 800m3 of concrete and 220 tons of steel), instrumentation work, surface drainage, 1 000 mm piping in FF (170 ml) and various works in the application of metalwork, floodgates and railings.

The preparatory work consisted of implantation and staking, drilling and wells, clearing and stripping and definition of borrow areas, sand, and aggregate exploration.

Many of the materials were locally produced and mined such as Rip-Rap, transition material or sands. In fact, the project was being developed and adapted to the specific conditions of the site and the materials present in the area. In addition, more economical solutions were sought than those initially envisaged.

The execution of the contract went through a critical phase, during the months of December 2021 and April 2022, in which the works were carried out under heavy rainfall, which caused some constraints in the execution of the works and the adoption of solutions to protect the works already executed, namely cofferdams, which forced the movement of a greater volume of earth.

In the final phase of the project, some tasks related to minor repairs and assembly of instrumentation mechanisms were carried out, namely piezometers and surface marks, to monitor the behavior of the structure, in view of the requests for which it was designed.