AfDB has praised quality construction works by the China Gezhouba Company.
The dam was expected to generate 500MW, expandable to 1,000MW.
More than 18,000 workers are now deployed on the project.
The government has so far spent over Sh36 billion on the project.
High Grand Falls Dam will hold 5.6 billion cubic metres of water.
China Jiangxi recently abandoned work on the site due to pending bills.
A total of 56 dams will be implemented under the PPP model.
The project has proved too costly and unattractive to investors.
China Jiangxi is demanding Sh846.5m before resuming excavation works.
The projects were discontinued in 2018 due to a financial scandal.