The delivery of two jumbo drilling rigs is expected to put construction of the Dakmi 4 hydroelectric project near Da Nang, Vietnam, back on schedule, according to Sandvik Mining and Construction.
Despite “severe rock conditions,” the two Sandvik rigs “are proving the key to keeping the tunneling contract on schedule,” the company said.
The 172-MW hydroelectric project is being built near the Cambodian border and includes a 420-meter long, 87-meter high dam to create a reservoir. But rock conditions in the tailrace tunnel are creating major problems for the drilling contractor, Sandvik said.
Specifically, the contractor has encountered “poor rock comprising sediment and badly fragmented and decomposed granite,” Sandvik said. Some rock bolting will be required, but the contractor is confident it can make up the lost time with the new rigs.